ADVERSE REACTIONS TO DRUGS When a new drug is introduced, it has usually been studied only in relatively few patients - typically 1,500. If patients have been studied, and no serious effects are observed, there is still a chance of a serious adverse effect's occurring in the general population as frequently as 3/n (1:500).
Adverse effects can be divided into types. First, those which are closely related to the concentration of the drug and accord with what is known of its pharmacology. These so-called type-A t(augmented pharmacological) effects are distinguished from type-B (bizarre) effects which are unpredictable, usually rare, and often severe, anaphylaxis is the most obvious of these, though bone-marrow suppression with co-trimoxazole, hepatic failure (see hepatitis) with sodium valproate, or pulmonary fibrosis with amiodarone would all be other examples. A more comprehensive classification includes reactions type С (chronic effects), D (delayed effects - such as teratogen-esis or carcinogenesis) and E (end-of-dose effects - withdrawal effects). Examples of adverse reactions include nausea, skin eruptions, jaundice, sleepiness and headaches.
Patients should remind their doctors
of any drug allergy, or adverse effect they have suffered in the past. Medical
warning bracelets are easily obtained. Doctors should report adverse effects to
the authorities, in the case of