Posts Tagged ‘ketotifen’

No single factor lies behind the allergy epidemic — the causes are many and various (see p. 20). What this means for parents interested in allergy prevention is that there is no

single measure which will ensure that your children do not develop allergies. Instead there are a great many different things that can be done, each of which reduces the risk to

some extent. The more of these you do, the lower the risk becomes.
Avoiding allergens
Starting before the birth is best, if you want to reduce allergen exposure for your child (see p. 240). But if you have missed the boat with that one, don’t despair – there is

still a lot to be gained by reducing allergen exposure at a later stage.
If you are ridding your home of allergens after the child’s birth, bear in mind that things will get worse before they get better– there will be a temporary surge in airborne

allergen as a result of the clean-up operation, and you will need to protect the child from this. The best strategy is for the child to be away for a few days while the work is

done, especially if you are taking out carpets, furniture or mattresses. Remember to protect yourself as well, if you are allergy-prone (see p. 109).
One of the most important steps you can take to reduce allergen levels is improve the natural ventilation of your home. This lowers the humidity (assuming you don’t live in an

extremely humid climate), which helps combat both moulds and dust mites. Ventilation also flushes out allergens in the air, especially cat, dog and mould allergens. Half the

problem with modern houses is that the airtight seals around doors and windows, introduced to conserve heat and save energy, turn the indoor air into a rich stew of allergens

and irritants.
House-dust mite
Avoiding high levels of house-dust mite in the home is one of the most valuable things you can do to reduce the risk of allergies in your child. Not only is house-dust mite a

powerful allergen in its own right, it may also act as an agent provocateur as far as the immune system is concerned (see p. 12), and may help to initiate allergic reactions to

other potential allergens – such as those from pets or indoor moulds.
Even if you do nothing else to protect your new baby from mite allergen, at least buy a new mattress and pillow for the cot, with ready-fitted allergen-proof covers. Do the same

for the portable crib, if you have one. Choose anti-mite products that are designed for babies and are guaranteed safe – there is a risk of suffocation with some loose covers

sold for older children and adults (see p. 245).
You may want to eliminate house-dust mite from your own bed as well as the baby’s, because there will probably be times when you take the baby into bed with you for a feed or a

cuddle – and times when, as a toddler, he or she just barges in! It is good to know that your child is still breathing air free from dust-mite allergen in these circumstances.
Deal with your own bed as soon as you can. Some doctors believe that lowering your exposure to dust mite during pregnancy may reduce the risk of sensitising your baby before

birth (see p. 241).
When taking anti-mite measures with your own bed, make sure that there is no risk of suffocation to the baby from the allergen-proof materials used. Microporous membranes based

on plastic could, if sucked onto the baby’s face during sleep, cause suffocation. Loose covers on duvets are worrying in this respect. Buy a new duvet with a built-in

allergen-proof cover, for preference, or a duvet that can be laundered at 60°C or above.
All the other measures for combating dust mites, described on pp. 114-17, will help to protect your child. Buy a good anti-allergen vacuum cleaner if you possibly can, and keep

your baby out of the room while vacuuming if you can’t (open the windows too). Make sure the baby only has new soft toys, preferably washable ones (see p. 116).
It is also an excellent idea to reduce dust-mite levels in the carpets and soft furnishings (see p. 117), because children tend to have very close contact with these in their

early years. A crawling baby, motoring enthusiastically around the sitting room floor, is stirring up the stockpile of dust-mite allergen that is found in any carpet, and

inhaling it in full measure. An adult walking around the same room has a far lower exposure, because dust-mite allergen, being relatively heavy, stays near the ground.
The best option is to go for non-carpet flooring, which doesn’t encourage dust mites. Parents tend to worry about the hardness of this, for a baby or toddler. In fact babies are

far more robust than we generally believe, and a hard floor is no problem for a small child who has never known the luxury of carpeting.
If you really hate the idea of your baby having anything other than carpet to play on, the next best option is to get new carpet, so that you start with zero dust mites. You

must then prevent dust-mite numbers from building up too much, by means of good ventilation, or with the use of a powerful dehumidifier (see p. 117).
Although the first year is the most vulnerable time for your baby, you mustn’t let your guard drop too much as time passes. The moment when a toddler moves from a cot to a ‘big

bed’ is sometimes the beginning of allergy symptoms because, after carefully protecting their child from dust mites in infancy, parents then put him or her into a bed with a

used mattress. This sudden exposure to a high dose of
dust-mite allergen can be the start of asthma. Get a new mattress if you can, and put allergen-proof covers on it. Alternatively, put allergen-proof covers on the existing

mattress.
Moulds
Mould spores are another potent allergen, and you should avoid bringing up a vulnerable child in a damp house if you can, because moulds will be growing there in abundance. Some

new research suggests that heavy exposure to mould allergens in childhood makes allergies in general much more likely. Even in a house that is not obviously damp, it is a good

plan to reduce indoor humidity (see p. 119). Carpets and furnishings that are full of mould spores (see p. 122) should be replaced.
Pets
What about pet allergens – should you find another home for your cat or dog when you are expecting a baby? This is a difficult question because the latest research shows that

pets are a double-edged sword as far as allergies are concerned.
A baby with allergic tendencies who is born into a house with a resident cat or dog is more likely to show allergic reactions to cats or dogs some years later. On the other

hand, there is research showing that having a pet in the house reduces the risk of allergies overall, especially for a child with no brothers or sisters. This is probably

because the pet boosts household levels of endotoxin (see p. 21), and generally makes the environment less hygienic for the child, fulfilling the same anti-allergy role as

brothers and sisters would in the early life of a child (see p. 246).
If you are planning to give your child the kind of grubby childhood that seems to protect against allergy (see p. 246), the additional protection provided by a pet is probably

unnecessary. Or, you could view your pet as having both pros and cons, and decide to keep it, while implementing all the other anti-allergy measures described here. If you do

this, ensure that the house is well ventilated (so pet allergens don’t build up to very high levels) and keep the pet out of the child’s bedroom so that he or she is not

breathing huge amounts of pet allergen while asleep. You could also wash the pet regularly (see p. 125) to reduce allergen levels.
If your child begins to show any signs of allergy to the pet, you must then find it another home.
Avoiding irritants
As well as increasing ventilation and eliminating cigarette smoke from the home completely, it may be worth evicting certain specific items that produce irritant gases.
The main ones are:
•    gas cookers (if you can’t afford to switch to an electric cooker, at least improve the ventilation in your kitchen as much as possible)
•    easy-clean plastic wall coverings and flooring
•    materials such as chipboard and MDF, which give off formaldehyde.
The evidence regarding the possible role of these in increasing the risk of allergies and asthma is described on pp. 128-9. In addition, although there is no evidence on this

point, common sense would suggest getting rid of any plastic or lacquered items that have a powerful smell.
Generally speaking, although traffic pollution can act as an irritant, it seems to play a lesser role in causing allergies and asthma than most people imagine. However, it may

sometimes play a part, especially if there are high levels of diesel fumes in the air (see p. 131).
Infections - friend or foe?
A large group of Italian military cadets were recently studied by doctors interested in the causes of allergy. By taking blood samples and testing them for antibodies to common

infections, the doctors could see what diseases the men had been exposed to early in life. At the same time, the young conscripts were assessed for allergies.
Allergies were least frequent among the young men with antibodies against three common infections that are dispersed via food and faeces – Hepatitis A, Toxoplasma gondii and

Helicobacter pylori. Only one in twelve of the cadets in this group had allergies.
Among the men with no antibodies against any of these infections, the rate of allergy was nearly three times as high – one in five of these cadets had allergies.
The doctors who carried out this experiment believe that these three infections are not necessarily important in themselves, but that they identify individuals who were ‘reared

in an environment that provides a higher exposure to many other orofecal or foodborne microbes’. In other words, they grew up in the kind of household where washing your hands

before meals wasn’t considered too important.
This study adds to the growing body of evidence (see p. 21) which shows that an over-clean environment during childhood encourages the development of an allergic disposition.
Those with lower rates of allergy include:
•    children raised on farms with livestock. The more exposure the children have to farm animals, the less the likelihood of them developing allergies.
•    children from homes with high levels of bacterial endotoxin in the household dust (see p. 21)
•    children who have fewer baths, and wash their hands less often (see p. 21)
•    children with brothers and sisters, especially those with older siblings. Some of the protection here may be due to the impact of the mother’s hormones and immune system

on the foetus in the womb: these effects change with successive pregnancies. But close contact with older siblings, and thus exposure to more microbes, probably plays a part.
•    children who go into kindergarten, nursery school or day care with other children at an early age – this is only valuable for children without brothers and sisters
•    children with pets at home – the benefits are much more pronounced for children without brothers and sisters.
The Italian study is especially important because, for the first time, it gives detailed information about the kinds of infections that make a difference in allergy prevention.

The military cadets were also checked for antibodies to measles, mumps, rubella, chickenpox and herpes. None of these infections gives protection against allergies – only

infections carried in food and faeces do.
Exactly what practical use you make of these discoveries is up to you. For most of us, the importance of hygiene was so firmly instilled during our own childhood that it is

quite hard to suddenly become more relaxed about it. But do let your children play in the garden, if you have one, and don’t worry so much about how dirty they get. Encourage

them to do some gardening – medical researchers believe that harmless bacteria in the soil may be particularly important in educating the immune system away from allergies (see

p. 21). Let them play with pets, as long as the animals are not carrying harmful parasitic worms (talk to your vet about whether pets should be treated for parasites). Ease up

or, hand-washing and, if this is your first baby, make sure he or she plays with other children as early in life as possible.
A few chest infections do seem to increase the risk of asthma, notably Respiratory Syncytial Virus (RSV). If this Infects babies, it provokes an IgE-reaction (see box on p. 12)

which may encourage the development of allergies. Unfortunately, there is very little you can do to protect your child from this common virus, but it makes sense not to take the

baby to a hospital for unnecessary trips (visiting relatives, for example) because RSV infections are often picked up in hospital.
Taking care with antibiotics
The possible role of antibiotics in making allergies more likely to develop is an exceedingly controversial topic. Before making any practical decisions in this respect, you

must consult your doctor. Never go against your doctor’s advice, if he or she thinks that antibiotics are necessary.
Several different studies have now produced evidence of a link between antibiotic use before the age of one or two, and the later development of allergies, asthma or both. The

best of these studies was carried out by doctors in Oxford, who followed 1900 children up to the age of sixteen. Among children at risk of allergy (because their mothers had

allergies) taking antibiotics before the age of two was linked with an increase in the rate of allergy from 32% to 54%. The more courses of antibiotics a child received, the

greater the risk.
The type of infection for which the drugs were prescribed was not important, as far as the risk of allergy was concerned, but the type of antibiotic did make a difference.

Broad-spectrum antibiotics, which kill a wide range of bacteria, were more risky –suggesting that the depletion of friendly bacteria in the gut (see p. 204) could be responsible

for increasing the allergy risk. Penicillins seemed less likely to promote allergies than erythromycin or cephalosporins.
This research is not widely known, as yet. And because there is a widespread assumption that giving an antibiotic can do no harm, even if it is unnecessary, antibiotics are

sometimes prescribed when they serve no purpose. In particular, antibiotics are often given for virus infections, especially in childhood, despite the fact that antibiotics are

of no value whatever against viruses. Research shows that doctors are sometimes responding to pressure from anxious parents when they prescribe antibiotics – it is difficult for

some parents to accept that a virus infection cannot easily be treated and just has to ‘run its course’. (Although there are drugs that combat viruses, these are expensive and

produce unpleasant side effects – they are reserved for very serious virus infections such as hepatitis.)
Obviously. when a child needs antibiotics to deal with a serious infection there can be no question about giving them. This is why you should always follow your doctor’s advice.

But it is also worth asking the doctor the following questions before giving antibiotics to your child:
•    are you sure that this is a bacterial infection, and not a virus infection?
•    would it be possible to do tests and check that it is a bacterial infection, before prescribing antibiotics?
•    what is the chance of the child overcoming the infection without antibiotics?
•    would it be dangerous to wait and see if the infection clears up naturally?
Vaccination
The same Oxford research team that investigated antibiotics (see left) also looked at the question of vaccination and allergy. They found a link between vaccination for

pertussis (whooping cough) and increases in asthma, eczema and hayfever. However the increases were not large, and a study from Sweden found that whooping cough vaccination did

not have any effect on rates of allergy and asthma. And researchers in Ethiopia have found that whooping cough vaccination actually reduces the risk of allergy in their country.
This is clearly a complex issue. The contradictory results from different parts of the world suggest that the ‘big picture’ is what counts here – the overall combination of

childhood infections, antibiotic treatment and exposure to harmless bacteria such as those in the soil or from animals. Depending on this big picture, vaccination against

whooping cough may push the allergy risk one way or the other.
There are many other arguments both for and against vaccination and, given our current state of ignorance about the possible effect on allergy, these other considerations are

probably more relevant. Discuss the matter in detail with your doctor before making a decision.

Doctors in Japan recently tried a very simple experiment in allergy prevention. They chose babies suffering from atopic eczema who were allergic to foods, but not allergic to

house-dust mite. Dividing the babies into two groups, the doctors put special allergen-proof covers, designed to protect against house-dust mite (see p. 115), on the mattresses

of all the babies in the first group. Babies in the second group were given ordinary cotton covers.
When the babies were one year old, they were tested again for allergy to house-dust mite. Two out of three children in the second group now gave a positive skin test to

house-dust mite.
By comparison, only one in three of the children from the first group gave a positive skin test. In other words, using the anti-allergy covers for these high-risk children had

cut by half the number who developed an allergic reaction to dust mite.
As this experiment shows, even if a child has already developed allergies, it is not too late to bring protective measures into play. Indeed, an allergy problem in infancy, such

as atopic eczema, can be seen as a warning sign to parents, telling them that they should reduce the child’s exposure to allergens as much as possible.
As well as reducing dust-mite levels, you should minimise your child’s exposure to moulds at home by limiting indoor humidity (see p. 119) and cleaning up any existing mould

growth (see pp. 122-3). This will lessen the chance of mould allergy developing.
Try to avoid staying, even temporarily, in any house that is damp or has old carpets and mattresses. When you are moving house, or carrying out any kind of renovation work,

remember that this will stir up a lot of dust-mite and mould allergens. Protect your child by arranging for a stay away from home.
This pro-active approach should not just apply to airborne
allergens, but also to food, in the opinion of some experts. They
suggest that any child with a true allergy to cow’s milk or egg
should not be given peanuts, tree nuts, fish or shellfish until three
years of age, to avoid sensitisation to these potent food allergens.
Pets are a more difficult issue, with both pros and cons as
regards allergy-prone children (see p. 245). If you decide to keep
your cat or dog, always ventilate the house well, and wash the animal regularly if you can (see p. 125). Be alert for your child developing an allergic reaction to your pet –

don’t turn a blind eye to the symptoms, as parents sometimes do because they are reluctant to accept that the child has become allergic to the family’s much-loved pet. If your

child does develop an allergy to the pet, the best option is to find the animal another home as quickly as possible (see p. 124).
Breast-fed babies with atopic eczema
Although breast-feeding is a good way of protecting children against atopic eczema, it is no guarantee. Sometimes babies become sensitised to food, in spite of being breast-fed,

and then they may react to traces of that same food, eaten by the mother and coming through in her breast milk.
Skin-prick tests (see p. 91) may help to identify the foods responsible for the eczema. Otherwise, a simple elimination diet by the mother, as used for colic (see p. 203), may

pinpoint the offending food. Keeping that food out of the mother’s diet will often clear the baby’s eczema.
Sometimes a breast-fed child’s eczema remains severe, despite the elimination of suspect foods from the mother’s diet. In this case, what should be done? New research from Or

Erika Isolauri – a staunch advocate of breast-feeding – suggests that the best option at this point is to stop breast-feeding promptly. Her research team found that breast-fed

children with persistent eczema had a slower growth rate. If these babies are switched to hypoallergenic formula – either an extensively hydrolysed formula or an artificial

amino-acid formula (see box on p.66) – their eczema symptoms usually subside, and their growth picks up.
Is vaccination safe for those with allergies?
The influenza vaccine and a few others (e.g. yellow fever) are grown in eggs and are not usually given to people with egg allergy. Measles vaccine is grown in cells taken from

eggs and may contain a minute trace of egg allergen, but only those who are extremely sensitive will react: there should be resuscitation equipment available for children who

have had anaphylactic reactions to egg and for those with severe asthma as well as egg allergy. Some vaccines come in vials with latex seals that are designed to be pierced by

the needle of the syringe. A different method should be used for latex-allergic patients. Smallpox vaccine (for bio-terrorism threats) is dangerous for children with atopic

eczema.
Never too late?
The role of modern ultra-clean lifestyles in promoting allergies is now well established (see p. 21). If your child already has allergies, it may seem as if these discoveries

have come too late to help —but that is not the case. Some research suggests that the battle for supremacy between Th1 and Th2 cells (see p. 11) — the unseen power struggle

which decides whether a child will be allergy-prone — is not really settled until some time between the ages of five and seven years. So there is still some potential for

intervening right up to this age. Some studies have suggested that the immune system can be pushed away from an allergic disposition at an even later age, right into adulthood,

by exposure to endotoxin, a bacterial product found around livestock and in `lived-in’ homes.
Several research groups are working on vaccination strategies (for example, using extracts of soil bacteria) that might also be able to achieve this. The initial results are

promising and they suggest that these vaccines can even help adults with allergies. Unfortunately, such treatments will not be available for many years. In the meantime, you can

probably reduce your child’s chance of developing new allergies, and perhaps make the existing ones less severe, by easing up on hygiene (see p. 246).
Fresh air and exercise
With the boom in watching TV and videos, and playing on computer games, some modern children hardly go outdoors at all. As far as allergies and asthma are concerned, there are

two big disadvantages to being a juvenile couch potato. For a start, the couch is also home to dust mites in their millions, and secondly the child is not running about and

using his or her lungs to the full. Airways that are never stretched (because the child never gets out of breath) lose their youthful flexibility in time. Once this has

happened, the airways can never be stretched to their full capacity. Some doctors believe that this may make asthma more likely to develop, or help to make it more severe once

it has developed. Inactivity also encourages obesity, which increases the risk of asthma developing.
Getting outside and running around, or engaging in other vigorous exercise, should be encouraged for any child with allergies. Obviously, you should balance this against the

need to protect the child from pollution peaks and (if your child has hayfever) pollen peaks. Children with exercise-induced asthma should use their reliever inhalers to allow

them to take exercise (see p. 41).
Keep the air at home free from irritants such as nitrogen dioxide (see p. 128), formaldehyde, air fresheners, paint, polish and strong-smelling cleaning fluids. These may

encourage new allergies to develop, and can make existing asthma worse.
Medical treatments
Antihistamines may have a preventive role in very young children with allergies. A study of one- to two-year-olds with atopic eczema found that the antihistamine cetirizine,

taken daily for 18 months, halved the chances of the children developing asthma later.
The children who benefited in this study were those with several risk factors for becoming asthmatic. They had moderate to severe atopic eczema, at least one close relative with

allergies, and allergic sensitisation to pollen or house-dust mite, as shown by skin-prick tests (see p. 91).
The cetirizine was taken at fairly low doses and had no bad effects on the children in this study. What is more, it seemed to benefit their skin as well as reducing the risk of

asthma: those taking the drug had less need of high-strength steroid creams. There is some controversy about the validity of these results, so few children with atopic eczema

are receiving antihistamines at present.
No one yet knows if other antihistamines might have the same effect as claimed for cetirizine. Ketotifen, which is an atypical antihistamine (see p. 159), may do so.
Immunotherapy may also have a protective effect. One study, involving children suffering from nasal allergies, found that those given immunotherapy were less likely to develop

asthma (see p. 165). Another study shows that immunotherapy for children with mite allergy halves the risk of their developing new allergic reactions to other allergens.

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).

Steroid inhalers
Most asthmatics nowadays are given a steroid inhaler at some point, as part of their asthma treatment (see p. 160). It will probably be a low-dose inhaler, and the risks of side effects from this are very small. Even at higher doses, inhaled steroids are relatively safe. Many people are unnecessarily afraid of inhaled steroids and refuse to use them until their asthma becomes really incapacitating. It is important not to delay using an inhaled steroid for too long, as this could cause permanent damage to the airways: inflammation eventually thickens the airway wall, leaving it less flexible and therefore less capable of widening.
For side effects of inhaled steroids see p. 145, and for common brand names see p. 147.
Steroid tablets
These are usually a treatment of last resort. But when you need them you need them – and if your asthma has got badly out of control, they can, quite literally, be a life-saver. On the other hand, if there are any other means by which you can tackle your asthma, so that you do not need steroid tablets again in the future –avoiding allergens and irritants, for example, or using other preventer treatments – those means should definitely be taken.
For side effects of steroid tablets see pp. 141-3, and for common brand names see p. 147.
Cromoglycate-type drugs
For asthma, these drugs are taken by inhalation only. They work by blocking the allergic reaction (see p. 148), and are therefore a type of preventer drug.
Cromoglycate-type drugs are usually inhaled four times a day, although your doctor may recommend more frequent inhalations to begin with. Once your asthma is well controlled, you may be able to reduce the dosing regime to three times a day, or possibly twice a day: ask your doctor’s advice about this.
Should you decide to stop taking these drugs at some point, talk to your doctor first. It is generally best to reduce the dose gradually, over a period of 7-10 days. Some asthmatics need to introduce (or reintroduce) steroids at this time, to maintain control of the airway inflammation.
Side effects
When inhaled, cromoglycate-type drugs can produce short-lived irritation in the throat, which may lead to coughing. This sometimes develops into temporary bronchospasm, causing you to wheeze, but this is really only a minor side effect – it does not indicate that the drug is making your asthma worse.
Asthmatics are sometimes advised to use a short-acting
beta-2 reliever (such as Ventolin) before their cromoglycate inhaler, to overcome this problem. However, this would involve using the beta-2 reliever four times a day, which is no longer considered a good idea (see pp. 153-4). Talk to your doctor again if you have been given this advice.
Inhalers that combine sodium cromoglycate with a short-acting beta-2 reliever (e.g. Aerocrom) are not recommended for the same reason.
A better way around the problem of throat irritation may be to switch to an aerosol inhaler, because the irritation is much less than with dry-powder inhalers. Using a spacer along with the aerosol inhaler (see p. 162) will help even more.
Serious side effects of these drugs are very rare (see p. 149). For common brand names, see p. 148.

Antihistamines and Allergy

Antihistamines were first introduced in 1947, and are very widely used, so their safety — at least in the case of the older antihistamines — is beyond doubt. Most of the antihistamines have no major ill effects, and no one should feel concerned about taking them. At worst they produce some rather annoying minor side effects, such as drowsiness, which often wear off in time.

These drugs are particularly valuable for hayfever and other allergies in the nose (perennial allergic rhinitis). They are also used for chronic urticaria, sometimes in combination with anotherhistamine-blocking drug — see p. 53.

Antihistamines are not much used for asthma. They have relatively little effect, probably because so many other messenger chemicals are involved in an asthma attack. However, doctors in Japan do use antihistamines for asthma, and it is possible that people of Asiatic origin react differently to them.

Only one antihistamine, ketotifen, is widely used for asthma in the West, and this has other effects besides blocking histamine (see p. 159). A new role may soon develop for antihistamines in thetreatment of asthma, combined with anti-leukotriene drugs (see p. 159).

If you suffer from anaphylaxis you might be given antihistamines in a liquid or chewable form, for use in an emergency. These are not enough in themselves to treat this dangerous condition - you must have an adrenaline injector (see p. 150).

In the past, some doctors prescribed antihistamines for atopic eczema, mainly for their sedative effect(see p. 139) which was thought to help children to sleep better and scratch less at night. This treatment has largely gone out of favour, because its value is in doubt. But a recent study has revealed that the non-sedating antihistamine cetirizine may be useful for very young children with atopic eczema, not only in treating their skin, but also in reducing the chance of them developing asthma (see p. 249).

Most people take their antihistamines in tablet or capsule form. Syrups and sugar-free elixirs areavailable for children.

Antihistamines can also be applied directly, in the form of nasal sprays or eye drops. These are mainlyused to treat hayfever and the conjunctivitis (inflammation of the eye) which often accompanies it.Levocabastine (brand name Livostin) is particularly effective for the eyes.

Antihistamine creams are also sold, without prescription, for the treatment of insect bites - i.e. thenormal non-allergic reaction to such bites. These creams are not recommended for atopic eczema or otherallergic conditions affecting the skin. Not only are they unlikely to help, but they may make mattersworse because, with regular use, skin sensitisation to the antihistamine occurs very readily (see pp.54-5).
Some common brand names

Common brand names include: non-sedating antihistamines - Clarityn, Semprex, Zirtek; Mistamine, Mizollen, Telfast, Terfenadine. Thefirst three are available without prescription.

older (sedating) antihistamines — Atarax, Dimotane, Optimine, Periactin, Piriton, Tavegil, Vallergan eye drops — Emadine, Livostin, Optilast nasal sprays — Livostin, Rhinolast

How antihistamines work
Of the messenger chemicals released when an allergic reaction occurs, the most important is histamine.

This does its work by attaching to specialised receptors in certain parts of the body, and so

triggering various reactions (see box on p. 12). The action of antihistamines is very simple: they bind

to the same receptors as histamine, but they do not trigger any reaction. Histamine cannot bind to the

receptor because the antihistamine is already there.
Unfortunately, the reverse is also true: if the histamine is already there, the antihistamine cannot

elbow it off the receptor, which is why it is important to take the antihistamine well before the

allergen is encountered. Taking antihistamines at the first sign of a snuffle or itch can also work,

but the effects will not be nearly as good as taking them in anticipation of an exposure.
The best approach to treating hayfever, for example, is to start taking the antihistamines at least a

week before the pollen season begins, and preferably two to three weeks before. You should then take

them continuously until it is over. This will make a huge difference to the degree of symptom control

you achieve.
Side effects
The older types of antihistamine, such as chlorphenamine (brand name, Rriton) are relatively

non-specific in their effects – they bind to several different kinds of receptors, not just those for

histamine. As a result they can have some unwanted effects, such as causing drowsiness and poor

coordination. While these sedative effects are no cause for concern in themselves, they can, of course,

be hazardous if you work with dangerous machinery or drive. Avoid both until you are sure how you react

to the antihistamine. Note that the effects of alcohol may be increased.
Very occasionally antihistamines have the opposite effect, causing stimulation rather than sedation;

this is most likely to occur in children and old people. Lowering the dose may solve the problem.
The other possible side effects of the older antihistamines –all of which are minor ones – are

headache, dry mouth, blurred vision, difficulty in passing urine, nervousness, shaky hands, upset

stomach or diarrhoea. A few men suffer impotence while taking antihistamines, but this disappears when

the drug is stopped.
The minor side effects of antihistamines, including drowsiness, often wear off after a while, although

the benefits of the drug remain. So it is worthwhile persisting with an antihistamine, even if it

causes some problems at first. Many people experience side effects from certain antihistamines but not

from others, so try several different types to find one that suits you.
The problem of drowsiness has been reduced, in recent years, thanks to the development of new drugs

that are far more
specific for histamine receptors, the non-sedating antihistamines. A few people do get drowsy even with

these drugs. Again, the effects vary from one drug to another, so if the first one disagrees with you,

try a different one.
It is worth noting – since some people may still have the odd packet in their medicine cabinet – that

two of the non-sedating antihistamines that were available without prescription a few years ago proved

to be unsafe for a small minority of people. One was astemizole (brand names: Hismanal, Pollon-eze),

which has now been withdrawn from use altogether in Britain. The other was terfenadine (brand names:

Triludan, Seldane, Terfenadine) which is still available, but only on prescription.
There are several special precautions relating to terfenadine:
• Never exceed the correct dose.
• If you have ever had any kind of heart problem, talk to your doctor before taking terfenadine.
• Stop taking the drug if you have palpitations, or if you feel faint; see your doctor promptly.
• Do not take terfenadine if you are taking the antibiotic erythromycin, or anti-fungal drugs

such as ketoconazole (Nizoral) or fluconazole (Diflucan), used to treat vaginal thrush.
• Do not take terfenadine if you have liver disease.
• Do not drink grapefruit juice while taking terfenadine: something found naturally in grapefruit

interacts unpleasantly with this antihistamine.
In addition to these special precautions concerning terfenadine, any antihistamine should be treated

with caution by those suffering from epilepsy, Parkinson’s disease, glaucoma, prostate enlargement,

kidney problems, urinary retention, a gastric ulcer, a thyroid disorder, porphyria or liver disease.

Check with your doctor before taking antihistamines if you have any of these conditions.
It may be inadvisable to use antihistamines if you are taking sleeping tablets, anti-depressants or

anti-anxiety drugs – again, see your doctor.
Stop taking antihistamines if you suffer any unusual kind of rash, or if your skin becomes more

sensitive to sunlight.
If you are breast-feeding, note that, because they go through into the milk, the older antihistamines

may make the baby sleepy. However, they do no harm.
Rescue treatment
Most antihistamines perform very badly if you take them once the allergic reaction has set in, but

acrivastine (Semprex) can be good in these circumstances and is non-sedating. No prescription is

required for this drug.
possibly identify all major side effects. We vary in our response to drugs, because we are all so

different at the chemical and cellular level. A drug might have a serious side effect that only affects

one person in 10,000, and no safety trial can hope to identify such a rare response. Only when a drug

is released, and becomes widely used, do such side effects come to light. Other unanticipated side

effects can sometimes arise when people taking the new drug are much older than those in the safety

trials, or belong to a different ethnic group with different susceptibilities. Combining the drug with

certain other drugs can also be a potential source of trouble, although pharmaceutical experts can

often predict such problems from a detailed knowledge of the chemistry of drugs and how they are broken

down in the body. Side effects that take several years to develop - more than the timespan of most

safety trials - will also fail to show up until the drug has been released.
All this may sound very alarming, but in fact severe reactions to new drugs are not that common. And

there are various safety nets in place - doctors keep a close eye on patients taking new drugs, and a

special reporting system ensures that, if unexpected side effects do show up, the information is

quickly shared with others in the medical community.
In order to relate the information here to a particular medicine that you take, you need to know what

drug category it belongs to. Does your inhaler contain a beta-2 reliever, a steroid, a cromoglycatetype

drug or an anti-cholinergic, for example? If you are not sure, ask your pharmacist.
Those are the category names for drugs: they denote families of drugs which are similar chemically
and work in roughly the same way. Within each category, or family, there are a number of individual

drugs. The individual drugs should, ideally, have a standard internationally agreed name - this is

known as the generic name. Unfortunately, a few of the drugs used for allergies and asthma have more

than one generic name - salbutamol is known as albuterol in some parts of the world, and adrenaline is called epinephrine.

Finally there are the brand names, which are the ones most patients are familiar with. These are always

shown with a capital letter, unlike the generic names. Long-established drugs are usually made by

several different pharmaceutical companies, and therefore marketed under several different brand names.

A newer drug, which is still covered by the patent of the pharmaceutical company that developed it,

will be sold under only one brand name.

The issue of brand names is important, because a different brand name might make you think you are taking a different drug, when in fact it is exactly the same drug being marketed in a different guise.If you have suffered side effects from a particular drug in the past, and wish to avoid it in future, take note of its generic name, rather than its brand name. Sometimes the generic name is used as the brand name, in what are called generic drugs. These arerelatively inexpensive copies of popular drug brands -they are just the same chemically, but they costless because there is no advertising of the brand to doctors, and profit margins have been cut to aminimum. In order to reduce National Health Service costs, doctors are now asked to prescribe generic drugs whenever possible.