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ANTIHISTAMINES
Histamine is a locally acting hormone. Contact with foreign substances that cause allergies is responsible for its release. Classically an allergic reaction with the release of histamine produces flushing of the skin and a weal. Dilation of capillaries and leakage of plasma from the circulation into the tissues cause these two effects. Such an effect is clearly seen in hives. With hay fever, the effect is not so visible but nasal blockage and the excess secretion of watery mucus testifies to the presence of this reaction inside a victim\'s nose.
Drugs used to counter the effects of histamine first appeared in 1947 and today many varieties are available over the counter at chemist shops. Unfortunately, most over the counter antihistamines cause drowsiness and potentiate the harmful effect of alcohol. Great care must be taken when driving or handling machinery.
Drug companies market three prescription only non sedating antihistamines called Teldane, Claratyne and Hismanal. The manufacturers point out that Hismanal, Claratyne and Teldane do not interfere with driving or the handling of machinery; nor do they potentiate the affects of alcohol.
The last decade also saw the range of antihistamines expand. Another type of histamine receptor called the H2 receptor triggers the release of acid for the purposes of digestion. Blockage of these receptors by newly developed H2 receptor blocking drugs consequently reduce gastric acid secretion and aid in the management of peptic ulcers. Two commonly used H2 receptor antagonists are Tagamet and Zantac. Tagamet and Zantac are now available without special authority on the Federal government\'s Pharmaceutical Benefit Scheme.
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GENERAL HEALTH
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