Posts Tagged ‘medicinal drugs’

Plants make a great many different chemical substances, mostly for the purposes of dissuading other living beings — fungi, insects and grazing animals — from consuming their

leaves, roots and fruits. These chemical substances are extraordinarily potent and diverse. Many taste disgusting, some are virulent poisons, and many will induce vomiting or

diarrhoea. None of these effects are surprising, given that substances such as these are produced to defend the plant. However, some of the chemical substances produced by

plants happen to have a beneficial drug-like action for people suffering from certain diseases. The effects of these substances are utilised in herbalism, sometimes known as

botanical medicine.
Over the millennia, herbalists have, through trial and error, tried to discover which plants have worthwhile effects. Indeed, this process probably began with our ape ancestors

– chimpanzees have been observed, when they are ill with parasitic infections, for example, to carefully select and eat particular leaves that have therapeutic effects. If

chimpanzees do this, it is a fair guess that the ape-like ancestors of human beings also did so.
At some point in human history – or prehistory – this use of wild plants became a systematic and specialised activity, now known as herbalism. No doubt the patients who went to

see herbalists (like patients visiting their doctors today) expected a cure for every ill, and no doubt herbalists felt bad about telling anyone that the problem was incurable.

At this point, quite a bit of wishful thinking and placebo effect (see p. 233) probably found its way into herbalism. The outcome was a mixed bag of herbal remedies – some that

worked, some that had no effect at all (apart from placebo effect), and a few that were positively toxic but whose bad effects escaped notice because of the seriousness of the

diseases being treated.
In recent times, a few herbal remedies have been put through rigorous scientific tests. As one might expect, some work and some don’t. More details of those that have been shown

to work
for allergies are given on p. 221. First, however, it is important to consider some of the misconceptions that surround herbal medicine, especially those relating to side

effects. These misconceptions are rooted in the basic philosophy of herbalism, so it is also important to look at this – and at other points of view about herbal treatment.
The ‘Mother Nature’ viewpoint
Some modern herbalists maintain that, for every human ill, nature has created a complete cure somewhere in the plant world – the job of herbalists is simply to identify that

cure. This belief is essentially religious and anthropocentric – that is, it assumes that the welfare of human beings is the central focus of the plant world. This goes against

common sense, because it suggests that plants produce a complex array of chemical components, not for their own benefit, but for ours.
A related idea, and one that is far more widely accepted, is that anything ‘natural’ must automatically be either harmless or positively beneficial to human beings. It’s a nice

idea, but nothing could be farther from the truth, as a quick survey of the plant world shows: hemlock is natural, belladonna is natural, and ricin –the most deadly poison known

– is natural. All come from plants.
Belladonna, of course, while being deadly poisonous in sufficient quantities, is also a medicinal plant. Its most significant ingredient, atropine, is a useful drug-like

substance in small amounts, and a poison in larger amounts. There is no sharp dividing line between these positive and negative aspects – even a small beneficial dose will have

some undesirable effects too.
In other words, herbs produce side effects, in just the same way that medicinal drugs do. This is almost inevitable – anything that alters body functions enough to act as a drug

will usually have some other unwanted effects.
In the case of herbal medicines, there is an added complication. Plants contain dozens, even hundreds, of different chemical substances, many of which have no benefits for

humans at all –they are just plain toxic. These plant toxins can produce various unpleasant effects of their own, to add to the side effects of the useful ingredients. So the

possibility of side effects is actually higher with herbal medicines than with medicinal drugs.
The side effects that occur with herbal treatment are sometimes very serious. Deaths have occurred in some cases, and in others, irreversible damage (e.g. to the liver) has been

done.
The ‘pure-is-best’ viewpoint
Many modern anti-allergy drugs were first obtained from plants –cromoglycate (see p. 148), for example, was originally extracted from the roots of an Egyptian plant called

ammivisnaga. The ground-up roots of this plant contain a great many other things besides cromoglycate, whereas the pharmaceutical preparations of cromoglycate are pure and of

known strength. This pure form of the drug has also been tested very thoroughly by pharmaceutical companies, in order to demonstrate its effectiveness, to identify the correct

dose, and to look for any serious side effects.
An advocate of scientific pharmacology would maintain that, with modern drugs, the patient is just taking the substance that works, not a mysterious cocktail of unknown plant

chemicals. In other words, you know what you are getting with a drug. You also know it has a good chance of working, and a relatively small chance of causing serious side

effects. With a herbal remedy, you are, to some extent, taking a leap in the dark.
Ephedra sinica, the herb known to the Chinese as Ma-huang, illustrates this point well. It contains a mixture of substances, including the powerful drug called ephedrine – it

was named after the plant. Ephedrine (see p. 156) can relieve the narrowing of the airways that occurs during an asthma attack. The presence of ephedrine gives Ma-huang the

ability to ease asthma, although it is more often recommended to help with weight loss. Unfortunately, over-use of Ma-huang can cause a spasmodic
contraction of the blood vessels in the brain, which can result in injury or death. Liver toxicity has also been recorded (see p. 220).
As for its anti-asthma ingredient, ephedrine, although this drug was once important in conventional asthma treatment, it is rarely prescribed now. Ephedrine has long been

superseded by other asthma-relievers that have a more precise effect on the airway muscles, and so produce fewer side effects.
The multiple-action viewpoint
Practitioners of Chinese herbal medicine, in preparing a treatment for atopic eczema, combine ten or more different herbs. There are some conditions, they say, that can be

treated with a single plant, but atopic eczema is not one of those. It requires a mixture – and none of the ingredients of that mixture, taken alone, has any effect. What they

are claiming is that the different drug-like substances in the herb mixture have a synergistic action, working together to treat the disease.
This same idea is sometimes applied to the many different chemical substances found in a single plant. Some herbalists argue that a herbal remedy is better than a modern drug

precisely because it contains a cocktail of different drug-like substances, the effect of one augmenting or balancing that of another.
There is no actual evidence to support this claim, but the fact that Chinese herbal mixtures have some success in treating difficult allergic diseases (see p. 221) demands that

Western doctors at least take the possibility of synergistic action seriously.
It might seem that this multiple-action viewpoint goes against the whole grain of Western scientific pharmacology – the ‘pure-isbest’ approach. However, Western medicine

frequently treats certain allergic diseases, such as asthma and chronic sinusitis, with a mixture of drugs.
Using herbal remedies safely
Always talk to your doctor before taking any herbal medicine, because of the risk of side effects, or interactions with any conventional drugs that you may be using.
If possible, get herbal treatment from someone who is also a doctor qualified in conventional medicine. Ideally, your herbalist should have access to laboratory facilities and

should order blood tests to monitor your reaction to the herb(s). Monitoring every 1-3 months is necessary with some herbs, to check for serious side effects such as toxicity to

the kidneys or liver (see p. 220).
Before buying herbal remedies from a health-food shop or via the Internet, contact the manufacturer and ask to see detailed reports of trials showing that the product is safe.
Think very carefully before taking a herb that has not The Chinese approach
One fundamental concept of Chinese medicine is that, rather than just matching the remedy to the disease, the treatment should also be based on the particular characteristics of

the patient concerned. This idea is shared by some other Eastern systems, such as Ayurvedic medicine.
Whereas a Western doctor might see you as a person with atopic eczema, a traditional Chinese doctor sees you as a person with a certain constitution which has got out of balance

and so produced symptoms in the skin. The constitution is usually the main focus of treatment, not the eczema. This approach means that different eczema patients get different

herb mixtures, and the same is true for other allergic diseases.
A traditional Chinese doctor will assess your constitution by taking your pulses (there are several in Chinese medicine, not just one), asking various questions, and studying

the appearance of your tongue – the same sort of diagnostic process that is used prior to acupuncture.
For the purposes of scientific investigations, where a uniform treatment is necessary, this traditional approach has been modified. A single standardised treatment is applied to

a particular disease – and the disease itself is diagnosed by Western medical criteria. Whether this is really comparable with traditional Chinese herbal medicine is open to

question. The same caveat applies to any off-the-peg Chinese herbal formula that is sold direct to the public, rather than being prescribed for an individual patient by a

trained practitioner.
The traditional philosophy of Chinese medicine makes for a lot of variability in herbal preparations. That is why categorical statements about side effects cannot be made –

while one mixture used for atopic eczema may contain a potentially toxic ingredient, another mixture may not.
undergone full safety trials. Find out all you can about the herb and discuss the matter with your doctor. Don’t fall for the ‘it must be safe – people have been taking it for

centuries’ argument. If a herb is only toxic to a minority of people, and its bad effects are slow to emerge (so people don’t get ill or die immediately after taking it for the

first time), its deadliness can escape notice for a very long time, perhaps indefinitely. In the case of pharmaceutical drugs, highly sophisticated information-gathering systems

are needed to ensure that such rare-and-slow effects are noticed (see p. 137) but nothing of the kind exists for herbal medicines.
Above all, do not neglect vital medical treatment (e.g. inhaled steroids for asthma) while trying out herbal remedies, as this can be dangerous. Always follow your doctor’s

advice about your drug treatment.
Risks to the liver
Among the side effects recorded for herbal treatment, liver damage is especially alarming. Deaths from liver failure have occurred with both Western and Chinese herbal

treatment. Liver toxicity has been recorded with the following herbal remedies: kava-kava, chaparral, germander, skullcap, mistletoe, senna, valerian root, jin bu huan, and

ma-huang or ephedra (Ephedra sinica). Some Chinese herbal teas prescribed for atopic eczema may also affect the liver, but this is not true of all eczema preparations – several

of the most widely used ones appear to be relatively safe.
Any medicinal herb might, in certain people, harm the liver. Should you feel ill while taking a herbal remedy, stop taking it immediately and see your doctor. The early symptoms

of liver toxicity, which you should watch out for, include jaundice (yellow
skin, and a yellowish tint to the whites of the eyes), pale faeces, dark urine, nausea and pain (usually in the region of the stomach).
Illicit steroids
Be very cautious indeed about pots of Chinese herbal cream sold for atopic eczema. Analysis of a selection of such creams found that two-thirds illicitly contained powerful

steroids – the very drugs that the people buying the creams were anxious to avoid. The dose of steroid in these herbal creams was alarmingly high, considering the purposes for

which some of them had been prescribed – such as use on the face of a baby. A substantial risk of serious side effects exists with these adulterated creams.
Sensitivity reactions to herbs
Like other natural products, herbs can provoke a true allergic reaction, and anyone with a tendency to allergies is at particular risk. Although any herb could, in theory, cause

such a reaction, some seem especially likely to do so:
•    Echinacea, which sometimes causes anaphylaxis or an asthma attack. Severe reactions may occur even in people taking it for the first time, if they are already allergic

to other plants in the daisy family (such as ragweed or mugwort).
•    Preparations containing royal jelly (obtained from honeybees) have sometimes caused near-fatal anaphylaxis in those allergic to pollen. Propolis, obtained from bees,

should also be treated with caution.
Contact dermatitis often occurs with tea tree oil and some other plant-derived substances applied to the skin (see p. 55).Herb—drug interactions
Using herbal remedies and taking medicinal drugs at the same time can be hazardous. These are the herbs that interact with anti-allergy drugs:
•    aloe vera, buckthorn, cascara sagrada bark, ginseng, and senna pod or leaf can all interact with steroid tablets
•    squill, lily of the valley and pheasant’s eye can increase the action and side effects of betamethasone (a steroid); rhubarb root also interacts with this drug
•    kava-kava, if taken with cetirizine (an antihistamine) can increase side effects such as drowsiness and poor coordination; it may have the same effect with other

antihistamines.
Note that many drugs prescribed for conditions other than allergies may interact with herbs. Some of these interactions can be serious, so check with your doctor before taking

any herbal medicine.
Herbs that may work for allergies
Of the herbal treatments that have been tested, the following appear to have potential benefits for people with allergies:
•    Chinese herbal teas for atopic eczema have shown good effects in scientific trials in Britain with both adults and children. Patients with widespread and persistent

eczema —which is particularly difficult to treat — were chosen for these trials. The puzzling thing is that when exactly the same herbal treatment was studied in Hong Kong, with

Chinese youngsters suffering from eczema, there was no improvement.
A combination of Chinese herbal medicine and acupuncture shows some limited benefits for hayfever patients (see p. 215). Pilot studies also suggest that a Chinese herbal

medicine formula may work for asthma.
More surprisingly, another mixture of herbs shows promise in reducing sensitivity for people with severe food allergy (so that there is less risk of fatal anaphylaxis from

accidentally eating the culprit food). Further research is needed to confirm these results. It is hoped that daily treatment for about six weeks will give 6-12 months’

protection.
If you are interested in trying Chinese herbal medicine, it is advisable to be monitored properly, as liver toxicity has sometimes occurred (see p. 220). See a reputable,

medically qualified practitioner, who can vouch for the contents of the herbal mixtures (imported ready-made mixes sometimes contain drugs such as steroids). Be warned that the

stuff tastes vile, and you have the daily chore of boiling it up before taking it. It can have a very mild laxative effect at first. Don’t use Chinese herbal creams unless they

are guaranteed steroid-free (see p. 220).
•    Euphorbia acaulis has shown good effects with atopic eczema. Liquorice root may also help, but can have serious side effects if taken in large amounts.
•    Evening primrose oil taken in capsule form, is known to calm inflammation, and might be helpful for atopic eczema. Don’t chew the capsules, as irritation of the throat

can occur. Epileptics should not take this oil.
•    Ginkgo biloba seems to reduce the reaction to allergens. For those with asthma it may also calm inflammation in the airways.
•    Ayurvedic medicine utilises two herbs, Coleus forskohN and Tylophora asthmatics, in the treatment of asthma. The former relaxes the airway muscles, in much the same way

as beta-2 reliever drugs, making the airways open up. The latter has more general benefits in asthma, but also some unpleasant side effects: it can cause nausea and soreness in

the mouth.
•    Saiboku-to is a Japanese herbal treatment for asthma. Studies suggest that it may have beneficial effects on airway inflammation and may allow a reduction in the dose of

steroids needed.
•    Butterbur has received a lot of publicity following a study which appeared to show that it was as good as the antihistamine cetirizine for hayfever However, the study

did not assess actual symptoms of hayfever, only the patients’ sense of wellbeing. Some preparations of this drug contain substances that could cause cancer, or carry a risk of

liver toxicity. Trials of butterbur for atopic eczema have shown no benefits.
•    Perilla seed oil appears to damp down allergic responses, and may help some asthma sufferers.
Omega-3 oils
These oils are derived from certain types of fish. They are obviously not herbs, but they are often sold alongside herbal remedies in health-food shops, which is why they are

included here. Generally speaking, omega-3 oils have a calming effect on inflammation,
but occasionally they provoke skin rashes, and asthmatics who are sensitive to aspirin may find that they gradually get worse if they take omega-3 oils. This is probably due to

problems with the production of messenger chemicals called prostaglandins in people with aspirin sensitivity (see box on p. 151). The connection is that omega-3 oils can act as

raw materials for the manufacture of prostaglandins and leukotrienes. The details of how omega-3 oils cause trouble for aspirin-sensitive people are not yet understood.

Elimination diet
An elimination diet is a method of diagnosing idiopathic food intolerance (see p. 74) and certain other

forms of food sensitivity where indirect tests, such as skin tests, are unhelpful. The principle of the

elimination diet is very simple. It begins by removing from the body every food that could possibly

cause a reaction, and seeing if this produces a symptom-free state. If it does, the elimination diet

then presents the body with different foods, each in its pure form, to see which ones cause symptoms.
While the principle is simple, the practicalities of the elimination diet can be much more complex, and

it is vital to understand the details fully before you start. There is absolutely no room for

‘cheating’ with this diet – one mouthful of cake is enough to ruin the whole thing. You need forward

planning and a lot of self-discipline, backed up by a good stock of the permitted foods for moments

when hunger overcomes you. Some cooked foods, stored in the freezer in individual portions for quick

defrosting, are a great help.
Doing an elimination diet incorrectly is not just a waste of time. Some people acquire new

sensitivities during the diet, which may make it very much more difficult to do a second elimination

diet. So plan ahead and get it right first time.
The planning stage
First of all, start an accurate symptom diary. This will give you a precise picture of how bad things

are now, before you try any dietary measures. A detailed daily symptom record, covering a period of

about two weeks, can be very useful, whether or not you actually do an elimination diet. It can serve
as a baseline against which to judge the effects of any future treatment.
Before you begin an elimination diet, you must see your doctor and ask if it is safe for you to do the

diet. Read through the next four pages first – the more you know about elimination diets, before

talking to your doctor, the better.
There are some conditions where, although an elimination diet can be very helpful, it should not be

attempted without full medical supervision. Two main causes for concern exist:
•    For people who are undernourished to start with, the elimination diet may be too demanding – it

is difficult to eat enough calories during the first few weeks of the diet, unless an elemental diet is

used as a supplement (see box on p. 196). If you are underweight, or have rheumatoid arthritis or

Crohn’s disease, the possible use of elemental diets is something you should discuss with your doctor.
•    With certain diseases (see list that follows), the testing stage may induce severe symptoms.

Sometimes these can be life-threatening and need immediate medical attention.
Medical supervision during food testing is recommended for anyone with these conditions:
•    Crohn’s disease – testing can bring on a prolonged relapse. Very small amounts of food should

be tested initially, and the quantity slowly increased.
•    Brittle asthma – after a period of avoidance, a culprit food can bring on a severe and possibly

life-threatening asthma attack.
•    Atopic eczema – the risk of reactions is higher if skin tests are positive (see p. 198).
•    Chronic urticaria – occasionally there is an immediate reaction to an offending food. It is

advisable to test foods in very small portions oust a mouthful) at first. If there is no reaction

whatever after four hours, a normal portion can be tested.
Note that an elimination diet is not suitable for anyone with true food allergy (see p. 62). If you

have ever had an immediate reaction to any food, or any symptoms in the lips or mouth, testing foods

can be dangerous. Caution is also necessary if you have ever reacted to a food with violent vomiting

and/or diarrhoea some hours after eating. This could be due to an infection, of course, but such

symptoms can also, very rarely, result from true food allergy (see p. 64). Finally, if you have ever

suffered anaphylaxis from any cause – not just food –the testing phase of an elimination diet might be

risky. Ask your doctor’s advice.
Once you have your doctor’s permission to try the diet, work out how the stages of the diet will fit in

with your life over the weeks or months ahead. Until it is over, eating food made by other people is

virtually out of the question. When eating away from home, you must either take prepared food with you,

or just eat very simple foods – such as permitted fruits or nuts. Think about the practicalities of

carrying food for meals away from home.
Finally, devise the diet you will follow during the exclusion phase (see right), locate shops that sell

the more unusual foods, and stock up on everything required.
You will continue to eat a lot of these foods for the first few weeks of the testing stage, so you may

want to buy extra stocks and refrigerate them for
longer storage, especially if the sources of supply are some distance from your home.
Note that food ingredients in medication could interfere with the results of the elimination diet. For

example, if you are very sensitive to maize (corn), the cornflour that is added to many antihistamines

and other drugs could create much confusion. Food-free medicines are available – talk to your

pharmacist about this initially, then to your doctor if you need a different prescription.
The exclusion phase
During the first part of an elimination diet, you exclude all the foods that you normally eat, plus any

closely related foods. For example, if you normally eat oranges, you should avoid all other citrus

fruits, including lemon, limes and grapefruit, even though you do not normally eat these. If you

normally eat plenty of broccoli, you should omit all its relatives, such as cabbage, kale, spring

greens and cress.
The best way to conduct the exclusion phase is not to follow a set menu, such as the well-known

‘Iamb-and-pears’ diet, but to draw up your own list of permitted foods. This can include foods that you

have never eaten before, and those you eat rarely.
The list should run to at least ten items. One problem with an exclusion phase that consists of only

two foods (as in the ‘Iamb-and-pears’ diet) is that you are bound to eat a huge amount of these foods.

This is asking for trouble if you have a tendency to food intolerance, because you can quite quickly

become sensitive to new foods if eating them in large amounts.
Your list of permitted foods should include:
Some starchy items. These are essential for keeping hunger at bay: try some of the more exotic root

crops, such as sweet potatoes, yams, dasheen and cassava. These are available in large supermarkets and

in small shops catering to Indian, African, Chinese and Caribbean communities. (Cook them as you would

potatoes. In the case of cassava, it must be boiled, not baked.) You can also eat parsnips, turnips,

chestnuts and pumpkin. Tapioca, sago, buckwheat, millet, quinoa and sorghum are other possibilities: a

health-food shop is a good source of some of these. Use rice if it is not normally part of your diet.

Do not include sweetcorn or maize meal, even though you do not normally eat these –corn products are

very widely used in packaged food, and sensitivity to corn is not uncommon.
Several fruits and vegetables that you don’t normally eat. Exotic produce such as mangoes and okra can

help a lot in keeping the diet tasty. Avocados, which are very rich and nutritious, can be included if

you don’t eat them often.
Some protein items. For carnivores, this is the easy part – any meat that you don’t normally eat is

suitable. Consider turkey, rabbit, pigeon or game, for example. (Soak rabbit meat in salt water

overnight to get rid of the strong taste, if you dislike this.) Strict vegetarians have more problems

here, since goat’s milk, sheep’s milk and all birds’ eggs are disallowed – their proteins are much too

similar to those of normal milk and eggs. Soya products such as tofu should definitely be avoided, as

should other pulses initially, because sensitivity to these is a possibility among vegetarians. Quorn,

or mycoprotein, could affect anyone sensitised to yeast, and should not be included. Fortunately the

exclusion phase is fairly brief, so a low intake of protein will not be disastrous. Including some nuts

on your list of permitted foods will help, as these contain protein. If nuts are part of your normal

diet, you may have to resort to rarely eaten kinds such as macadamias, cashews or pistachios.
Elemental diets
An elemental diet is a powder that contains all the nutrients the human body needs but is free from the

substances in food that provoke allergic and intolerance reactions. It is mixed with water to create a

complete substitute for food. Originally designed for space travel, this totally synthetic form of

sustenance is also known as ‘the astronaut’s diet’.
Used alone during the exclusion phase, elemental diets are the basis for the ultimate – and

theoretically foolproof – elimination diet. They sustain you through the exclusion phase, and continue

to provide your basic diet during the testing phase.
For anyone with multiple food sensitivity, using an elemental diet circumvents the problem of finding

ten or more safe foods with which the elimination diet can begin.
Those who are underweight can also benefit from using an elemental diet, simply as a calorie-boosting

supplement during the exclusion phase and testing phase.
Unfortunately, elemental diets taste fairly unpleasant and are quite expensive. You
may need a prescription, so talk to your doctor. Ideally you should get an elemental diet that does not

contain sucrose (sugar).
Some items that make good snacks. Nuts, pumpkin seeds, sunflower seeds, fresh fruit and dried fruit are

all useful for times when you are away from home, or feel hungry between meals. At the outset of the

diet, use only unsulphured dried fruit –available from health-food shops. At a later stage, you can

test ordinary dried fruit (all of which is treated with sulphur preservatives – see box on p. 207).
A cooking oil, preferably one that you have not used much in the past. Use this fairly liberally, to

keep the calorie content of your diet at a reasonable level
Note that this is a very plain diet – you eat the permitted foods and absolutely nothing else. You

cannot use spices, herbs or other flavourings. Salt is allowed, but sugar is out, as are tea, coffee,

alcohol and all soft drinks. You must drink only mineral water and pure juices from permitted fruits.
Don’t use canned or packaged versions of the permitted foods. Buy raw food and cook it yourself. The

idea is to avoid food additives and other contaminants, such as those from the linings of cans.
Throughout this phase, and the next, you must be very careful not to eat too much of any one food.

Never eat any food every day, and stay away from any food that you begin to develop a real passion for

– this is always a bad sign in people with food intolerance. It is better to go a little hungry

(assuming you are not underweight to start with) rather than binge on any of the permitted foods.

Acquiring new sensitivities is all too easy.
Assuming you do have food intolerance, and you have excluded all the foods that affect you, there

should be a complete clearance of symptoms within 7-10 days. The response is usually unmistakable. A

partial or slight response is probably just a coincidence, and should be discounted, except for those

with rheumatoid arthritis (see below).
Be warned that you may feel a great deal worse before you get better. For those who do have idiopathic

food intolerance, the first 5-6 days of the diet can be very unpleasant – usually they suffer the same

symptoms as before the diet, but far more severe.
Some conditions, such as Crohn’s disease and rheumatoid arthritis, may require a longer exclusion

phase, but there is no point in continuing beyond three weeks. Bear in mind that long-term structural

damage to arthritic joints may prevent a complete recovery. A partial but sustained improvement in the

joints, accompanied by a distinct improvement in general health, suggests that food could well be

playing a part in causing the disease, and that it is worth going on to the testing phase.
Symptoms that are only intermittent, such as chronic urticaria or migraine, pose a special problem. You

need to decide, before starting the diet, how long the exclusion phase should continue in order to give

you a clear sign that your state of health is improved. A symptom diary is vital here. If, for example,

your symptom diary shows that you sometimes have a week that is symptom-free but you never get through

two weeks without an attack, then your exclusion phase should continue for two weeks.
You should only go on to the testing phase if you improve during the exclusion phase. If you do not

improve, you have excluded the possibility of food intolerance, and can give up the diet.
The testing phase
This part of the diet, which is sometimes called the reintroduction phase, takes about eight weeks. It

requires careful observation of your symptoms, and constant self-discipline about everything you eat.

You should not stop or delay the testing unless you are ill – it is vitally important to complete it as

quickly as possible.
Foods have to be reintroduced one at a time, with a space between in which symptoms can be observed. It

sounds simple, but this is where errors can easily occur.
During this phase, as well as noting your symptoms daily, you should also record absolutely everything

you eat.
For the first 2-3 weeks you should test foods that are unlikely to cause symptoms. Start by testing

fruits, vegetables and meats that you do not eat very often normally, but which you do like. If they

pass the test, you can use them to vary your diet. This will make life much easier and reduce the risk

of developing new sensitivities.
Next test foods that you do eat reasonably often, but not every day. Leave the most likely culprits –

the foods you eat very regularly, such as wheat and milk products – until you have established a safe

diet that contains at least 25 different foods. This safe and relatively varied diet should be the

backdrop against which you test staple foods.
The testing procedure changes over time, because your sensitivity may decline as the diet progresses.

During the first eight weeks, you should test one food each day, eating a normal-sized portion for

lunch or supper. A reaction to the food might occur quite soon after the meal, or some hours later. Any

symptoms that occur within the following 24 hours should be provisionally attributed to that food.
Unfortunately, bowel symptoms can sometimes take longer to develop – up to 48 hours. This can confuse

things when a new food is being tested every day.
There may also be uncertainty about intermittent conditions such as chronic urticaria. You may not be

absolutely sure that the problem really responded to the exclusion phase. If so, when the symptoms

recur during the testing phase, this may be due to a food, or it may just be coincidence.
Should there be any doubt about which food caused a particular set of symptoms, cut out all the suspect

foods for now, and retest them after a couple of weeks, using a three-day testing procedure (see

below).
When a reaction does occur to a food, stop all testing and go back to the safe diet until you feel

completely better. But don’t wait too long before resuming testing. You need to get through most of the

testing within eight weeks because, for some people, intolerance to the foods begins to fade after

that.
This does not mean that the intolerance has been ‘cured’, unfortunately. A period of eating the food

regularly will soon bring the problem back.
If you are still testing foods after eight weeks, you must change to three-day testing – eat a normal

portion of the food every day for three days, stopping only if you get symptoms. Should you have no

reaction to the food by the end of the fourth day, you can consider it safe. (But leave it out of your

diet for at least another four days.)
There are some special procedures for testing certain foods:
•    When you test wheat, even if it is quite early on, use the three-day test procedure (see

above). Reactions to wheat can be very slow. (If you have rheumatoid arthritis, you should spend a full

five days testing wheat, and eat it at least twice a day.) Don’t use bread to test wheat because this

also contains yeast and other ingredients. Use a pure wheat cereal such as Shredded Wheat – moisten it

with fruit juice if you cannot have milk. Note that some people who react to whole-wheat are sensitive

to the wheat germ, and can tolerate refined wheat, as in white bread and flour. For others only white

flour is a problem – they are usually reacting to additives in the white flour. Careful testing will

sort out these issues.
•    Test milk before cheese and butter. You may react to one but not the others. If you react to

fresh milk, wait a few weeks, then test evaporated milk. Later, you can test goat’s milk and then

sheep’s milk. Some people can tolerate these, but must be very careful not to consume too much of them.
•    You can test yeast using Marmite or yeast-based B-vitamin tablets. Do this before you test

mushrooms, •    At some point, test a canned food. This is to check for reactions to the lining

material used on cans. Choose something that contains no other ingredients or additives, such as

carrots. Test it first in a frozen or fresh form, so that you are sure you don’t have a reaction to the

food itself.
•    Throughout the testing period, continue with cooking all your own food from scratch. At a

fairly late stage in the testing, when you have tested most foods, spend three days eating packaged

food. The idea is to eat a wide range of different food additives all at once. Read the labels

carefully (see p. 172) to check that all the food ingredients are ones which you have already tested

and found safe. You are unlikely to react to these packaged foods, but if you do, you should then

conduct tests with all the individual food additives. You may need some help from a dietitian for this

(see p. 201).
Testing becomes more and more uncertain after 12 weeks. If you
have not completed it by then, reintroduce all the untested foods.
Should your symptoms come back, cut out all those foods again,
then test them individually.
What next?
For anyone who recovers during an elimination diet, and successfully identifies their problem foods, a

period of complete abstinence from those foods follows. After about a year, it is worth testing the

foods again, as the sensitivity may have subsided. (Don’t do this if you have rheumatoid arthritis –

see p. 23.)
If, after a year or two, you find that a food no longer makes you ill, don’t go back to your old ways –

remember that you must only eat the food occasionally. Once every three or four bays is a good rule of

thumb for a food to which you were previously intolerant. You might get away with having it slightly

more often than this, but never go back to eating it daily. If it starts to become your ‘favourite

food’ again – the thing you fancy more often than anything else – watch out.
Good nutrition is an important issue for anyone avoiding certain key foods. If you have cut out all

milk products, for example, you should probably be taking a calcium supplement, unless you eat a lot of

other calcium-rich foods. Ask your doctor to refer you to a dietician or nutritionist if you feel you

need help.
An elimination diet for children with eczema
Before putting your child on any kind of restrictive diet, it is vital that you talk to your doctor.

The risks of malnutrition are far higher for children, and there can be serious long-term consequences,

such as stunted growth or impaired intelligence. You must therefore have medical consent and

supervision for an elimination diet.
For young children with atopic eczema, there is rarely any need for a stringent elimination diet, such

as that described on pp. 194-7. Children are usually sensitised to only one or two commonly eaten

foods.
In the case of recently weaned infants, it is enough to simply cut out individual foods, one at a time.

Avoid each food for two weeks, while observing symptoms carefully.
For older children a simple elimination diet, with an exclusion phase which avoids just the most likely

culprits, works well. The foods that you should exclude at the outset are:
•    any food which has given a positive skin-prick test (see p. 69)
•    any food which you think may have caused digestive symptoms, such as diarrhoea, either now or

in the past
•    eggs, milk and all milk products
•    beef and chicken
•    citrus fruits (oranges, lemons etc.)
•    food additives.
If the child’s skin is no better after a week of this diet, cut out the following foods as well:
•    peanuts and other nuts
•    soya
•    fish
•    wheat and maize (corn)
•    tomatoes
•    lamb.
If there is no response after another week, food is unlikely to be contributing to the eczema.
For the testing phase, use three-day testing, as described on p. 197, if you have fewer than ten foods

to test. Use one-day testing if you have more than ten foods to test.
You should begin by testing a very small amount of the food. Wait ten minutes for any symptoms (not

just skin symptoms – the mouth or stomach may also be affected) then give a little more if nothing has

happened. Build up gradually to testing a normal portion of the food.
A more cautious approach is required for children who give positive skin-prick tests to foods, or have

a history of symptoms in the mouth or digestive tract. They are more likely to suffer severe symptoms

in the lips, mouth and throat – the type of reaction associated with food allergy. Emergency medical

treatment may be needed. You can see if there is any likelihood of a severe immediate reaction to foods

by starting with a test on the face, and then the outer lip (see box on p. 23). If nothing happens, it

is probably safe to go on to the next stage – giving the child a very small amount of the food to eat.

However, you should have medical supervision for Rare reactions
Very occasionally, atopic eczema sufferers on milk-avoidance diets develop a sensitivity reaction to

calcium supplements. There is no scientific explanation for this, but it has been very well documented

in two children. Should you encounter this problem, the answer may be some alternative natural source

of calcium: sardines or other small fish, eaten whole, are one possibility, assuming your child will

eat fish. A dietician can advise on how much is needed per day.
There has also been one well-documented report of a child reacting to mineral water. When the water she

usually drank was changed to another brand, her eczema cleared up. This is very unlikely to be a common

problem.
this procedure in the case of foods that gave positive skin tests. If your child has both severe eczema

and additional symptoms (such as nettle rash, or symptoms in the mouth or digestive tract) it may be

advisable to have medical supervision when testing all foods.
Bear in mind that atopic eczema naturally fluctuates a great deal. To observe the effects of trying out

a food, you need the child’s skin to be in a steady state. That means being absolutely consistent about

applying steroids and moisturisers, avoiding (for the period of testing) any stressful situations that

could provoke a flare-up, not exposing the skin to sudden doses of irritants or airborne allergens, and

keeping scratching under control. Be aware of other factors that could muddy the waters by provoking a

flare-up of eczema – such as teething, or a cold (see p. 44).
If certain foods are identified as provoking eczema symptoms, and you decide to cut the food from your

child’s diet, a nutritional supplement may well be needed. Ask your doctor to refer you to a

nutritionist or dietician.
Other diagnostic diets
These diets are not used by (or even known to) the majority of doctors. While some, such as the

low-nickel diet, have been subjected to rigorous scientific testing and have shown their worth, others

have not been tested scientifically. The evidence in favour of them is purely anecdotal – in other

words, doctors have used these treatments repeatedly and observed good results with some of their

patients. That is not hard science, but it is how innovations in medicine often begin.
There are few risks with any of these diets – the number of foods to be avoided is small, and you are

most unlikely to become malnourished. Your doctor should not object to you trying any of these diets,

however sceptical he or she may be about its possible benefits.
Low-nickel diet
This diet is sometimes of benefit to adults with eczema. There are various pointers which indicate that

the diet may help, as described on pp. 55-6.
Make sure that you have absolutely no contact with any nickel (e.g. in jewellery, jeans studs, watches

or hair clips) throughout this diet, and for at least two weeks before starting it.
Ideally you should also stop treatment with steroids or antihistamines a week or so before starting the

diet. This allows any improvement to be easily observed. Obviously you should get your doctor’s

permission to do this.
The diet could take anything from six weeks to six months to take full effect. Some people have a

complete clearance of their eczema, while for others there is a partial but distinct improvement.
The foods with a high nickel content, which should be avoided as far as possible, are:
•    shellfish
•    green beans and peas
•    beansprouts and lucerne sprouts
•    dry beans and lentils (pulses) of all kinds; soya protein and products containing it (e.g.

vegetarian sausages and burgers)
•    spinach and kale
•    lettuce, leeks
•    wheat bran (avoid bran cereals and other products; replace wholemeal bread with white bread, or

eat it in moderation only – you can get plenty of fibre from fruits and vegetables; do not eat

multi-grain breads at all)
•    oatmeal, millet and buckwheat
•    raspberries, prunes, pineapple, figs
•    chocolate and cocoa
•    tea from drinks dispensers (restrict intake of other tea and coffee, and don’t make them too

strong)
•    peanuts, hazelnuts, almonds and marzipan
•    liquorice
•    sunflower seeds, linseed
•    baking powder, in large amounts
•    vitamin or mineral preparations that contain nickel (check the label carefully), Nickel is also

found in drinking water, and absorbed from certain cooking utensils, so:
•    Do not use items plated with nickel (e.g. tea balls, some tea strainers, egg beaters). The

extremely shiny appearance of nickel makes these easy to recognise.
•    Do not cook acid fruits in stainless steel pans, since the acid leaches some nickel out of the

stainless steel. An enamel cooking pot is safe.
•    Minimise the amount of tinned food that you eat.
•    In the morning, run off the first litre of water from the tap, as this may contain nickel

released from the tap itself.
Several other foods and drinks seem to aggravate the skin of nickel-sensitive people, even though the

foods are not rich in nickel. These foods and drinks should also be avoided:
•    beer, wine
•    herring, mackerel, tuna
•tomatoes, carrots, onions, apples; oranges and other citrus fruits, including their juices.
Low-chromium and low-cobalt diets
Skin sensitivity to chromium or cobalt can, very occasionally, result in a tendency to react to these

same metals when consumed in food or drink (see pp. 56).
Unfortunately, both chromium and cobalt are essential for good nutrition, so avoiding them is fraught

with problems. You would need the help of a really good dietician, or a doctor with a particular

interest in nutritional problems, to guide you through a diet of this kind.
The only measure you can safely take at home is to cut down on excessive consumption of these metals,

for three weeks only, to see if this produces any improvement in your symptoms. If it does, that should

encourage you to seek expert help for a more thorough avoidance diet.
In the case of cobalt sensitivity avoid:
•    all canned and bottled beer.
In the case of chromium sensitivity avoid:
•    beer, wine and cider
•    yeast extract and yeast tablets
•    black pepper
•    calf’s liver
•    wheatgerm and wholemeal bread
•    cheese.
If you also have nickel sensitivity, avoid nickel-rich foods (see p. 199) at the same time.
Low-histamine diet
Histamine in food is mostly produced by bacterial action. The majority of people can break down any

histamine they eat, as long as the amount is not excessive (see box on p. 67).
Temporary susceptibility to histamine may accompany viral hepatitis or other liver conditions.
A permanently impaired ability to detoxify histamine is relatively unusual. When it does occur it can

result in symptoms such as chronic urticaria, migraine or recurrent headaches. A low-histamine diet may

help in these cases. All of the following should be avoided:
Very high histamine content:
•    red wine, champagne
•    tuna, sardines
•    Emmenthal and Camembert cheeses.
High histamine content:
•    beer, white wine
•    anchovies
•    Gouda, Roquefort, Stilton and all other well-matured cheeses
•    salami and other well-matured sausages, Westphalian ham
•    sauerkraut
•    spinach
•    tomato ketchup.
If you improve only partially on this diet, this may indicate that you are on the right track

(histamine is indeed the problem) but that the bacteria in your gut are undermining your efforts with

the additional histamine which they generate. You can investigate this possibility by trying a

low-carbohydrate diet, as described on p. 53.
Low-amine diet
Naturally occurring substances called amines, found in many different foods, can have a drug-like

effect on the blood vessels, making them open up a little and so increasing the blood flow. The effect

is usually small, but some people are more susceptible than others. A low-amine diet is worth trying if

you have chronic urticaria or migraines, and have not improved with other treatments. A low-amine diet

can also be useful in atopic eczema: amines in food are not a basic cause of eczema, but they can

aggravate the rash by increasing blood flow to the skin. To begin with, cut out all foods listed below:
Very high amine content:
•    all cheeses except cottage cheese
•    dark or plain chocolate
•    yeast extract (Marmite etc.), miso, tempeh, tomato paste, tandoori spice mix, stock cubes,

ready-made sauces •    cola drinks, orange juice, tomato juice
•    any dried, pickled or smoked fish
•    sausages, pies and smoked meats, beef liver, chicken skin
•    broad beans, spinach
•    sauerkraut
•    almonds.
High or moderate amine content:
•    milk chocolate
•    soy sauce
•    beer, wine and cider
•    pork, including bacon and ham, salami, chicken liver, offal
•    all fresh or tinned fish, except white fish
•    all nuts except chestnuts and cashews
•    sesame seeds, sunflower seeds
•    avocados, aubergines, mushrooms, tomatoes, broccoli, cauliflower
•    olives and olive oil
•    oranges, lemons and other citrus fruits
•    pineapples, bananas, raspberries, strawberries, pineapples, plums, grapes, dates, figs, kiwi

fruit, passion fruit.
Continue for at least three weeks, and longer if your symptoms are normally intermittent. if you

improve, you can then experiment with reintroducing small portions of foods from the second list, three

or four times a week. Gradually build up to a higher intake, but cut back if your symptoms return.
Organic diet
The objective here is to avoid pesticides, i.e. chemical sprays applied to kill fungi and insect pests.

This may be helpful for people with chemical intolerance (see p. 84).
`Chemical-free’ or ‘unsprayed’ food (crops grown without pesticides) will do just as well as 100%

organic food (which is grown without either pesticides or artificial fertilisers).
The highest intake of pesticides is from fresh fruit and vegetables, so if your budget is tight,

concentrate on buying organic or chemical-free versions of these. If you have a garden, growing some of

your own food will reduce the cost.
You can also reduce the pesticide content of ordinary fruits and vegetables by:
•    Storing them for as long as possible before using them, because the pesticides break down quite

quickly
•    Always peeling them. With difficult-to-peel items such as peaches and tomatoes, pour boiling

water over them and leave them to stand for a few minutes first, as this loosens the skin. Rinse in

cold water, then peel.
•    If peeling is not possible, washing them very well with soap or detergent, then rinsing them

thoroughly
•    Cooking them, as this drives off some of the pesticides; avoid inhaling the steam and ventilate

the kitchen well while doing this.
You should drink mineral water from a reputable source, or use a very high-quality water filter (not a

jug filter).
Additive-free diet
Food additives are occasionally the culprit in chronic urticaria (see p. 53). At the same time as

avoiding additives, people with chronic urticaria should cut out other potential culprits – alcohol,

spices and all aspirin-like drugs (see box on p. 151).
An additive-free diet may also be of value for some people with chemical intolerance (see p. 84).
In the case of children with Attention Deficit Disorder (ADD), also called Hyperkinetic Syndrome, the

role of additive-free diets is a contentious issue (see p. 81).
An additive-free diet is very healthy but quite hard work. It means making all your own food from 100%

fresh, unmodified produce (you cannot have bacon or ham, and even things like cooked chicken and

ready-to-eat salad can contain some additives; so does most restaurant food). Note that wines, beers

and other alcoholic drinks can contain many additives without declaring them on the label. (German

bottled beer is an exception here.) Baked goods sold unwrapped can also contain many additives without

declaring them.
Stop using toothpaste unless it is an additive-free brand. You can buy such toothpaste from a

health-food shop – or use sodium bicarbonate powder instead. Drink mineral water or filtered water (you

need a good-quality filter for this, not a jug filter).
Medicinal drugs can contain colourings and other additives, so you should try to get additive-free

versions. Talk to your pharmacist about this initially.
Assuming the symptoms clear up, testing can begin, but you will probably need medical help to work out

exactly which additives are at fault. It is difficult to organise these tests at home, because most

foods contain such a mixture of additives.
With chronic urticaria, there is the possibility of quite severe reactions on testing, so medical

supervision is desirable. You can undertake cautious testing with small amounts of tap water, spices

and alcohol at home, but make sure you are in a position to get emergency medical help if you need it.

Aspirin or aspirin-like drugs should not be tested at home. Life-threatening reactions are common in

sensitive individuals, and temporary avoidance can heighten your reaction.

Theophylline
Theophylline-type drugs are also known as xanthines or methylxanthines. These drugs are chemically similar to caffeine. They cannot be inhaled, so are taken as tablets or syrup. They start working about 30 minutes after being taken and their effects last for 6-8 hours. Slow-release preparations take 90 minutes to start working, but they last 12-24 hours, and are therefore useful for nocturnal asthma.
In Britain, doctors generally regard theophylline-type drugs as reliever drugs (see p. 152), but rather risky ones whose use is only justified for people with severe asthma. They are given, as an additional treatment, to asthmatics who are not responding well to the usual drug programme (see p. 160). Unfortunately, fairly high doses are needed for theophylline-type drugs to act as relievers, i.e. to reverse bronchospasm. There is a very narrow margin between such a dose and one that causes major (and sometimes dangerous) side effects.
Such side effects usually occur when the doctor is still trying to work out the correct dose – this varies from one person to another, so prescribing theophylline-type drugs is no easy matter. Once you are established on a safe dose (and provided your general health and your intake of alcohol, nicotine and medicinal drugs does not vary – see p. 158) you can usually continue taking theophylline without serious side effects.
In the United States, many doctors also give theophyllinetype drugs, at much lower doses, to people with mild asthma. At these low doses they do not act as relievers, but they have a slight anti-inflammatory effect and therefore act as preventers. The risk of toxicity is much less. Taking low doses of theophylline allows people with mild asthma to reduce their use of beta-2 relievers. However, inhaled steroids are usually more effective in this role, and are the preferred treatment outside the United States.
Side effects
Typical side effects include nausea, vomiting, stomach pains, diarrhoea (sometimes with blood), headache, anxiety, restlessness, insomnia, dizziness, and a pounding heart or irregular heartbeat.
Any side effect of these drugs should be taken seriously and reported to your doctor as soon as possible. If you cannot get an appointment quickly, it may be best to stop taking the drug before seeing the doctor, as long as you have other drugs to control your asthma. Call your doctor for advice.
It is remarkably easy to overdose when taking these drugs at higher doses (see p. 157). Such overdoses can be fatal. The symptoms include repeated vomiting, shaking, feeling unusually hot, needing to urinate frequently, severe thirst, maniacal behaviour, and irregular heartbeat (palpitations). Delirium and convulsions may occur shortly afterwards, so get hospital treatment urgently if you have any of these symptoms.
Unfortunately, a serious overdose can sometimes occur in people who have taken theophylline-type drugs without trouble for many years. There may be no advance warning that anything is wrong - no mild side effects preceding the serious ones. To protect yourself against this, you need regular blood tests from your doctor.
One fundamental problem with theophylline-type drugs is that many different factors - including diet, illnesses other than asthma, and taking other drugs - can alter the way your body deals with the drug. If your liver is breaking down the drug more slowly than usual, the amount in your blood will rapidly increase, and can reach toxic levels.
These are steps that can help prevent an overdose with theophylline-type drugs:
• If you start taking a new drug of any kind, or stop taking a drug (especially the contraceptive pill), or if you change your intake of nicotine or alcohol, ask your doctor - preferably in advance - if your dose of theophylline-type drug needs to be changed.
• A great many drugs interact with theophylline-type drugs, including the new anti - leukotriene drugs. You should always be cautious with any new drug, but take particular care with two antibiotics - ciprofloxacin (brand name Ciproxin) and erythromycin (various brand names) - and with cimetidine (various brand names), used for stomach ulcers and heartburn.
• If you have flu vaccinations, or develop certain illnesses, especially viral infections, heart disease or liver disease, watch for the typical side effects of theophylline-type drugs (see above) and consult your doctor immediately if any occur. These conditions all change the effects of theophylline-type drugs.
• Don’t eat meals that are very high in fats or oils. A lot of fatty food causes too much of the drug to be released at once from the slow-release preparations and increases the risk of side effects. Avoid sudden, major, changes to your diet.
• See your doctor regularly for check-ups. Simply getting older changes your reaction to these drugs: your dose may need to change over the years.
• If you are at all forgetful about tablets, keep a careful record of when you have taken your theophylline-type drugs. Be very careful never to take a second dose by mistake.
• Talk to your doctor if you are not taking a slow-release form of theophylline (see box below for brand names). There are usually fewer side effects from these than from the ordinary forms of the drug.
• Wear a Medic Alert bracelet (see box on p. 95) saying that you are taking theophylline-type drugs. If you have a severe asthma attack and are taken to hospital, it is important that medical staff know this, so that they do not give you more drugs of this type.
While pregnant or breast-feeding, it may be advisable to stop taking theophylline-type drugs: discuss this with your doctor. Although the drugs do not affect most unborn or newborn babies, there are occasional reports of toxicity. Less seriously, theophylline-type drugs go through into breast milk, and may make babies irritable and restless. This problem can be solved by always taking the drug just after a feed - this reduces the amount in the milk.
Theophylline-type drugs might produce behavioural problems and learning difficulties in young children although this is unproven. Research shows that there are no problems for children over six.
Anti-IgE drugs
For asthmatics with strong allergic reactions, who are not doing well on ordinary treatment, the new anti-IgE drugs, such as omalizumab may be very valuable (see p. 149). They are given as a depot injection under the skin.
Some common brand names
Common brand names of theophylline-type drugs include: slow-release preparations — Lasma, Nuelin SA, Phyllocontin Continus, Slo-Phyllin, Theo-Dur, Uniphyllin Continus
ordinary preparations - Aminophylline, Nuelin Ketotifen
Ketotifen (brand name Zaditen) is an antihistamine (see p. 138), although it has other effects in addition to those of ordinary antihistamines. Most significantly, it stabilises mast cells in a similar way to cromoglycate.
One advantage of ketotifen to many people is that it is taken by mouth, in capsule, tablet or syrup form. When it was first introduced, doctors hoped that it would be of particular help in asthma, but it has not lived up to expectations. However, some asthmatics do find it effective. It is worth trying because, it it works, it could permit you to reduce your dose of steroids.
Ketotifen requires up to six weeks to take effect, so continue taking your previous drugs (e.g. steroids) for at least six weeks, or you will risk losing control of your asthma.
Side effects
Minor side effects from ketotifen include nausea, headache, increased appetite and weight gain, drowsiness, dry mouth and slight dizziness. Do not drive until you are sure that ketotifen does not make you drowsy. Alcohol may pack a more powerful punch than usual, so drink very moderately at first. If drowsiness is a problem, take the drug in the late evening. The sleepy feeling may wear off after a few weeks of taking the drug.
There are no serious side effects from ketotifen, except if taken with drugs for diabetes.
Anti-leukotriene drugs
Leukotrienes are among the messenger chemicals that are produced by mast cells during an allergic reaction (see box on p. 12). They help to perpetuate the inflammatory process begun by histamine, and they amplify the reaction by attracting more immune cells into the area.
The anti - leukotriene drugs fall into two distinct groups:
• those that bind to the receptors for leukotrienes, called leu kotriene- receptor antagonists. Currently, there are two drugs in this group, montelukast (brand name Singulair) and zafirlukast (brand name Accolate). A third drug, pranlukast, is in the pipeline and currently going through its safety trials.
• those that block the production of the leukotrienes altogether, called 5-lipoxygenase inhibitors. There is only one drug in this group at present, zileuton (brand names Leutrol, Zyflo); it is not yet available in Britain.
As regards tackling inflammation, the anti - leukotriene drugs work in a completely different way from either steroids or cromoglycate. This makes them useful as an add-on treatment, supplementing the effects of existing anti-allergy drugs.
For asthmatics, anti-leukotriene drugs may be particularly good in combination with antihistamines – whereas antihistamines alone are singularly unsuccessful in asthma (see p. 138). Recent research suggests that taking antihistamines together with antileukotriene drugs is an effective way to control airway inflammation. However, there have been no large-scale trials of this treatment option yet, and it may be a while before it comes into general use.
In the airways of people with asthma, leukotrienes can directly trigger bronchospasm (contraction of the airway muscles) as well as fostering inflammation and increasing mucus production. This multiple action of leukotrienes makes anti-leukotriene drugs very valuable for asthmatics because they act as both relievers (reversing bronchospasm) and preventers (tackling inflammation). They are especially useful for exercise-induced asthma.
All the anti-leukotriene drugs are taken in tablet form. If you are trying an anti - leu kotriene drug for the first time, don’t expect any noticeable effects to occur for about three days. Once you are taking the drug regularly, each dose requires 2-4 hours to have its full effect, but goes on working for 12-24 hours in total.
Although anti - leu kotriene drugs have a reliever effect, they cannot give you immediate relief from bronchospasm. Asthmatics must therefore carry a short-acting beta-2 reliever (see pp. 152-3) as well, in case of an asthma attack.
For those who dislike inhalers, or tend to forget to use them, the fact that these drugs are taken once a day in tablet form makes them an attractive option. However, they are expensive, and at present doctors prescribe them mainly for young children who have difficulty inhaling their usual drugs.
Side effects
The side effects noted in safety trials of these drugs were all minor ones:
• zafirlukast – headache, nausea, diarrhoea, pain
• montelukast – headache, diarrhoea, abdominal pain, cough, and flu-like symptoms
• zileuton – upset stomach
As with all new drugs, you should report any unusual symptoms to your doctor, just in case these represent a rare or longterm side effect of the drug (see p. 137).
Very occasionally montelukast provokes allergic reactions, with symptoms such as itchiness, widespread nettle rash (urticaria) or swelling (angioedema).
Zafirlukast and zileuton can both cause liver damage, but this is rare. Your liver function should be closely monitored by the doctor, by means of regular blood tests, and the drug withdrawn at the first sign of trouble. Montelukast can also affect the liver, but this is extremely rare.
The most worrying development noticed to date is the appearance, in a very few people taking zafirlukast or montelukast, of a disorder called Churg-Strauss Syndrome. The symptoms may include a blotchy purplish rash (due to vasculitis – see lower box on p. 73), a flu-like illness, worsening asthma, and numbness or tingling in the limbs. The heart, lungs and nerves are all affected, because eosinophils (see p. 19) are present in large numbers and cause damaging inflammation.
A study of the cases reported so far suggests that this syndrome may not be due to the anti-leukotriene drugs themselves but to other causes – usually (though not always) a reduction in the dose of steroids. Other patients who are not taking antileukotriene drugs, but are reducing or stopping steroids, may also (again, very rarely) develop Churg-Strauss Syndrome. Doctors now suspect that all these patients were already suffering from an underlying eosinophilic disease, which first showed itself simply as asthma, and was quelled by the steroid treatment prescribed for the asthma. The disease was thoroughly masked as long as the patient was using steroids, but when steroids were withdrawn, the underlying disease flared up, producing a wide range of symptoms. In most cases, reintroducing steroids brings these symptoms under control again.
Putting it all together
What is the ideal combination of all these asthma drugs? That is something your doctor can only work out slowly, because it varies from one individual to another.
The conventional approach to asthma treatment is to start patients on a short-acting beta-2 reliever and then, if the symptoms are not controlled, to add other drugs. This approach is called ’stepping up’. The standard steps, or stages, are as follows:
1. Use a short-acting beta-2 reliever only.
2. Add cromoglycate or low-dose inhaled steroids.
3. Try a higher dose of inhaled steroid or a long-acting beta-2 reliever.
4. Try out each of the following in turn: theophylline, anticholinergic drugs, cromoglycate and higher doses of beta-2 relievers (either inhaled or as tablets/syrup).
5. If there is still no success in controlling symptoms, add regular steroid tablets.
Short courses of steroid tablets may be used at any stage, for the control of sudden, severe, attacks.
Over the last ten years, there has been a change of strategy, and very few people are now kept on Stage 1. Inhaled steroids are now given to most asthmatics, even those with relatively mild asthma. Research from Sweden, where widespread use of
inhaled steroids first became general policy, shows considerable benefits to this approach.
If you have gone beyond Stage 2, ’stepping up’ is usually followed by ’stepping down’. In other words, when the symptoms have been well controlled for 3-6 months, doses of some drugs are reduced, or certain drugs stopped altogether. If the asthma flares up again, the dose is increased or the drug reinstated. If there are no problems, and symptoms remain stable for a month or two, another reduction is tried.
An entirely different approach to asthma management is now being tried with some patients – starting off with moderate to high doses of inhaled steroids (equivalent to Stage 3) and then ’stepping down’. The idea is to get the inflammation under control promptly and fully at the outset. This often seems to be the best strategy.
A few asthmatics don’t get much benefit from steroids. If your dose of steroid needs to be raised repeatedly, or you still need to use your reliever daily in spite of taking steroids, you may have steroid-resistant asthma. There are other drugs that can help, including anti-leukotriene drugs and the more powerful anti-allergy drugs (see p. 149).
Alcohol, caffeine and asthma
Some asthmatics experience bronchodilation (opening up of the airways) when they drink alcohol, while others experience
bronchospasm (tightening of the airways). For those whose airways open up, there is probably no harm in sometimes having a drink to relieve your asthma symptoms, assuming these are fairly mild. Clearly, it would not be a good idea to make a daily habit of this.
If your airways tighten up with alcohol, you will probably be pleased to hear that it may not be the alcohol itself. Alcoholic drinks contain a great variety of other ingredients, either derived from the original ingredients or generated during the fermentation process. Called ‘congeners’, these vary from one type of alcoholic drink to another, and they are often the culprits in asthma. So you may well find that, while one kind of alcoholic drink has a bad effect, another is fine.
Caffeine has a far more uniform effect — for most asthmatics it opens up the airways. However, the amount needed to relieve an asthma attack will also produce unpleasant side effects, such as a pounding heart or shaky hands. There are also long-term problems with such high doses of caffeine, including insomnia, headaches, nervousness and ‘restless legs’. It is much better to use your reliever inhaler to control an attack: the drug in the inhaler has been chemically tailored to give the maximum therapeutic benefit with the minimum of side effects. Anyone who consumes tea or coffee excessively can make themselves seriously ill, either physically or mentally, and it is not always obvious that caffeine is the cause (see p. 235).