Adverse drug reactions during treatment of hypertension.

Adverse drug reactions (ADRs) can be broadly classified as either "a nuisance" or "life-threatening". Voluntary reporting systems gradually accumulate a quite impressive list of suspected ADRs with antihypertensive drugs as their use becomes widespread. Such data gives no clue to true or relative incidence. The absolute and comparative incidence of ADRs can only be determined fairly by a system of unbiased general data collection of ADRs from which the data for antihypertensive drugs is then selected. The Boston Collaborative Drug Surveillance Program provides such a source of information. Data from the Boston Program reveals that most of the listed ADRs with antihypertensive drugs occur very infrequently, that "nuisance" ADRs occur in 10 to 29% of patients in whom they are used, and that "life-threatening" ADRs occur in less than 1%. ADRs tend to discourage patient compliance with medication aims. In selecting specific antihypertensive therapy the clinician should be mindful not only of the severity of the hypertension to be treated, but also of the nature, type, and severity of potential ADRs, the personality and likely complicance of the patient, and the need for patient education regarding drug effects, possible unwanted effects, and what measures should be taken when ADRs occur.