Which of the following is NOT an example of CHRONIC adverse drug reactions:

Ans. (a) Nitrate induced headacheRef.:KDT 6th ed. / 78* According to WHO, adverse drug reaction (ADR) is defined as any noxious, unintentional, and undesired effect of a drug, which occurs at doses used in humans for prophylaxis, diagnosis, or therapy. These may be classified asType A: Augmented pharmacologic effects -- These are dose dependent and predictable. These are basically the extension of the pharmacological effects of a drug, e.g. hypotension caused by antihypertensives, headache caused by vasodilators (like nitrates).Type B: Bizarre effects (or idiosyncratic) -- These are dose independent and unpredictable, e.g. agranulocytosis caused by chloramphenicol.Type C: Chronic effects: These are seen on long term use of the drug over a long period, e.g. Glucocorticoid induced osteoporosis, chloroquine induced retinopathy, amiodarone deposition in cornea etc.Type D: Delayed effects: These are seen long after the drug has been stopped e.g. teratogenic effect of drugs like thalidomide.Type E: End-of-treatment effects: These include the withdrawal effect of drugs e.g. rebound hypertension due to clonidine withdrawal.NOTE: Nitrate induced vasodilation and headache occur immediately, these are not chronic adverse drug reactions whereas others are example of type C or chronic ADRs.