Adverse drug reactions in current antihypertensive therapy: a general practice survey of 2586 patients in Norway.

The objective of this study was to determine the frequency and profile of adverse reactions to antihypertensive drugs in an unselected group of drug-treated hypertensive patients. A questionnaire-based survey was carried out among 2586 drug-treated hypertensive patients who attended a general practitioner for clinical control. Adverse drug reactions reported spontaneously, upon general inquiry, upon specific questioning and as evaluated by a physician were used as the main outcome measures. The study shows that the percentage of patients who reported adverse drug reactions spontaneously, upon general inquiry and upon specific questioning were 16%, 24% and 62% respectively. Users of diuretics reported the lowest frequency of adverse reactions, whereas users of beta-blockers reported the highest frequency. In 7% of the patients, the adverse drug reactions were of such a nature that the physicians considered discontinuing the treatment. As a conclusion, the reported frequency of adverse drug reactions in antihypertensive treatment is high, but with significant differences between the various drug groups. Monotherapy is connected with far fewer adverse drug reactions than combination therapy.