Posts Tagged ‘Vallergan’

triamcinolone A glucocorticosteroid with the actions, uses and side-effects of hydrocortisone, but differing by promoting sodium excretion, and so is of no value in adrenal cortex deficiency states. It is used in a wide range of inflammatory, allergic and respiratory states, and in inflammatory skin conditions.
Dose: 8-24 mg daily. It is also given as triamcinolone acetonide in doses of 40 ing by deep i.m. injection for a depot action. The acetonide is also given by iniraarticular injection in doses of 2.5-40 mg in local inflammation of the joints, and by intra-lesional injection in doses of 2-3 mg at any one site for the treatment of skin lesions. Triamcinolone actonide is also used as a 1% cream or ointment in severe inflammatory skin conditions. The side-effects are those of the corticosteroids (see hydrocortisone), but triamcinolone may also cause myopathy with high dose treatment. (Kenalog; Ledercort).
triamterene A potassium sparing diuretic, used mainly in association with more powerful drugs. It is indicated in oedematous conditions generally, and, as it causes some retention of potassium, its use avoids the need for supplementary potassium therapy.
Dose: 150-250 mg daily, with lower doses for the elderly and when given in association with other diuretics. Rash .ind gastrointestinal disturbances are ,ide-effects. (Dytac). See page 148 and Kahle 21.
tribavarin An inhibitor of viral replication used in severe viral bronchiolitis in infants.
Dose: by aerosol inhalation of a solution (20 ing/ml) for 12-18 hours daily liar 3-7 days, together with supportive therapy. (Viravid).
triclofos A derivative of chloral, with the sedative properties of the parent drug, but less irritant to the gastric mucosa.
Dose: I 2gdaily.
alternative to penicillamine in other conditions. The main side-effect is nausea.
trifluoperazine A powerful tranquillizing drug of the chlorpromazine type. It is used mainly in schizophrenia and similar psychoses, and in severe anxiety.
Dose: 10-20 nig or more daily according to need. In severe anxiety, 2-6 ing daily. In acute conditions, 1-3 mg daily by deep i.m. injection. As an antiemetic, it is given in doses of 2-4 mg or 1-3 ing by injection. The side-effects are similar to those of chlorpromazine, including extra-pyramidal symptoms, but the anticholinergic and sedative side-effects are less severe. (Stelayine). See page 168 and Table 30.
tri-iodothyronine See liothyronine.
trilostane An inhibitor of enzyme systems concerned with production of mineraloand glucocorticosteroids by the adrenal cortex, and so resembles metyrapone to some extent. It is used to control adrenal cortex hyperfunction and the excessive production of aldosterone.
Dose: 240 ing daily initially, adjusted tip to a maximum of 480 mg daily, according to the plasma corticosteroid levels. Care is necessary in liver and kidney dysfunction. (Modrenal).
trimeprazine A sedative antihistamine used in the treatment of pruritus and allergic itching conditions, and for premedication.
Dose: 30-100nig daily; pre-medication dose: 3 mg/kg. (Vallergan).
trimetaphan A short-acting ganglionic-blocking agent. It is used to produce a controllable reduction in blood pressure (luring neuro- and vascular surgery when a relatively bloodless field is necessary. Dose: by i.v. infusion, 3-4 nighnin initially, with subsequent doses carefully adjusted to the response. Side-effects are tachycardia and respiratory depression. Frequent determination of blood pressure during use is essential.
triclosan A chlorinated phenolic antiseptic, used mainly in surgical scrubs and similar preparations. (Manusept; Ster-Zac).
trientine A copper-chelating agent used in Wilson’s disease, but only for patients unable to tolerate penicillamine.
Dose: 1.2 -2.4 g daily. It is not an
trimethoprim An antibacterial agent similar in action to the sulphonamides. It is used in the prophylaxis and treatment of urinary tract and respiratory infections due to sensitive bacteria.
Dose: in chronic infections, 200-400 nig daily; prophylactic dose, 100mg daily. In severe infections, 130-250 mg twice daily by slow i.v. injection. Side-effects are nausea, vomiting,rash and pruritus, and possible bone marrow depression. (lpral;
Monotrim). See co-trimoxaole.
trimetrexateV An antibacterial agent used like atovaquone in AIDS patients with Pnettinocystis carinii pneumonia.
Dose: 45 ing/nidaily by i.v. infusion for 21 (lays, followed by calcium folinate 80 nighty daily for 28 days, orally or i.v. (Neutrexin).
I Tyr
oral antidiabetic drugs by increasing the sensitivity to endogenous insulin, and so acts as an insulin enhancer.
Dose: 200 mg daily with breakfast, increased if required by 200 mg at intervals of 2-4 weeks up to 600 mg daily. Side-effects are diarrhoea, fatigue and malaise. (Romozin). See page 131 and Table 13.
tropicamide A short-acting mydriatic agent similar to homatropine. Used as 0.5% and I% solution.
trimipramine A sedative anti-depressant with the action and side-effects of amitriptyline. It is valuable in depression complicated by anxiety.
Dose: 75-300 mg daily. (Surmontil).
triple vaccine Diphtheria, tetanus and pertussis vaccine for the primary ininitinization ofchildren.
Dose: 0.5 ml by i.m. or deep s.c. injection.
triptorelin A synthetic form of gonadorelin, used in the treatment of advanced prostatic cancer. Such cancers are testosterone-dependent, and triptorelin acts by depressing pituitary function, and so indirectly reduces the plasma level of testosterone.
Dose: It has been formulated so that a single i.m. injection of 4.2 ing depresses testosterone production for 28 days. Initially there may be a temporary flare-up of symptoms, which can be prevented by giving an anti-androgen for 3 days before treatment, and continued for 2-3 weeks. Patients should be monitored for uleric obstruction and spinal cord compression during the first months of treatment. DecapepivI Sr). See page 122.
tropisetron A 5–HT.,-receptor antagonist, similar to ondansetron bill with a longer action. It is used to control the nausea and vomiting induced by cancer chemotherapy.
Dose: initially as a 5 mg dose i.v. shortly before such therapy, and followed 1)), oral doses of 5 mg daily, I hour before food, for 5 days. Side-effects are dizziness, headache and gastrointestinal disturbance. (Navoban). See page 122.
tryparsamide Used in late trypansomiasis when the CNS is involved.
Dose: 1-3 g by injection weekly, up to a maximum Lill) of 24 g. May damage optic nerves.
tryptophan\7 An amino acid involved in the biosynthesis of serotonin. It is used in specialist centres for the treatment of severe and prolonged depression resistant to other drugs, and where a deficiency of serotonin may be a factor. (Optimax). See page 128 and Table 11.
tuberculin A product obtained from cultures of Mycobacterium tuberculosis. It is used in the diagnosis of tuberculosis. See BGC vaccine.
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trisodium edetate A chelating or binding agent that is sometimes used in hypercalcaernia. The calcium complex so formed is excreted in the urine.
Dose: slow i.v. infusion tip to 70 rng1kg daily according to need and response, as shown by plasma calcium measurement. It is also used as a 0.4% solution for
ophthalmic use in lime burns of the eyes. Side-effects after injection are nausea, diarrhoea and cramp. Contraindicated in renal impairment. (Limclair).
troglitazone A new drug for non-insulin dependent diabetes. It differs from other
tulobuterol A selective beta,-adrenergic agonist of the salbutamol type, used in the prophylaxis and treatment of bronchospasm in asthma and related conditions. Dose: 4-6 mg daily. (Respacal). See page 118 and’fable 6.
tyrothricin A minor antibiotic used as
lozenges for mouth infections.

undecenoic acid An organic acid with useful antimycotic properties. It is used mainly as powder or ointment (5%), often with zinc undecenoate in the treatment of athlete’s foot and associated conditions.
urea An osmotic diuretic. It has been used orally in doses of 5-15 g. Applied locally as a 10% solution, it promotes granulation and reduces odour front•    foul ulcers.
urofollitrophin A preparation of human lollide-stimulating hormone (FSH) used with nienotrophin for the induction of ovulation. Dose and duration of treatment require careful control to avoid Over-stimulation. (Metrodin; Orgafol).
I Vas
allergen vaccines, used for desensitization to various allergens such as grass pollens, arc not true vaccines, but weak solutions of allergen extracts. They may precipitate allergic reactions in susceptible patients, and should be used only when emergency resuscitation measures are immediately available.
valaciclovirV A pro-drug of acyclovir used in herpes zoster. It is well absorbed orally, and quickly converted to the parent drug and promotes an improved response.
Dose: 3 g daily for 7 days, reduce([ in severe renal impairment. Dose in herpes simplex I g daily. Side-effects are headache and nausea. (Valtrcx). See page 144 and Table 19.
valproic acid (Convulex). See sodium valproate.
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urokinase A plasmin activator obtained from human urine. It is used mainly in the thrombolysis of blocked i.v. shunts, and in the lysis of blood clots in the eye. Dose: 5000-37 500 units, instilled into the shunt; similar doses are injected into the anterior chamber of the eye for the resolution ofl)l blood clots. (Ukidan).
ursodeoxycholic acid The acid appears to be a solvent of cholesterol, and is given orally to promote the dissolution of cholesterol-containing gall stones.
Dose: 8-12 mg/kg as a single daily dose, hut prolonged treatment is required, which should be continued after the dissolution of the stones to inhibit recurrence. The dissolution of calcium-containing or radio-opaque stones is unlikely to occur. (Destolit; Ursofalk).
valsartan An angiotensin II receptor antagonist used in hypertension. It has a more selective action than the ACE-inhibitors. Dose: 80 mg daily. Combined treatment with a potassium-sparing diuretic is not advisable. (Diovan). See page 148 and Table 21.
vancomycin An antibiotic used in severe antibiotic-associated staphylococcal colitis ( pseudomembranous colitis).
Dose: 0.5 g daily for i-10 days. It is also given by injection in resistant bacterial endocarditis; I g twice a day by slow i.v. infusion over 1-2 hours, as rapid injection may cause anaphylactic shock. Blood concentrations of the antibiotic should be monitored, as the many side-effects include renal damage, ototoxicity and ncutropenia. Pruritus and upper body flushing may occur, and tinnitus is an indication that the drug should be withdrawn. (Vancocin).
vaccines Bacterial vaccines are suspensions or extracts of dead bacteria, but sonic anti-viral vaccines are also available. They may be given by s.c. or i.m. injection, and are used mainly for prophylaxis against a particular infection. The most commonly used vaccines include those for typhoid, cholera, diphtheria, influenza, tetanus and polio. Protection against mumps, measles, pertussis, rubella, yellow fever and hepatitis can also be obtained. The so-called
vasoconstrictors Drugs such as noradrenaline that constrict the peripheral vessels, and so cause a temporary rise in blood pressure. They are useful in hypotensive conditions when the blood volume is still adequate, and in controlling the fall in blood pressure that occurs in spinal and general anaesthesia.

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.