[Study of the effect of season on the frequency of side effects or antihypertensive agents]

To evaluate the influence of season on side effects of antihypertensive treatments in hypertensive patients followed by cardiologists.

In 12,071 hypertensive subjects, referred to cardiologists, a questionnaire with 14 possible side effects due to antihypertensive treatment was administered during the consultation. Details on antihypertensive treatment and cardiovascular characteristics were obtained from medical records. This evaluation was obtained in patients recruited during summer (7,438 patients) and during winter (4,633 patients).

In this population of treated hypertensives, blood pressure level was < 140/90 mmHg in 28%, and 50% were treated with a monotherapy. At least one side effect was declared by 40% of cases, and it was observed dyspnea (10%), dizziness (8%), fatigue (8%), palpitations (6%), ankle oedema (5%), headaches (5%). The higher rate was observed in patients on monotherapy, most frequent side effects were fatigue (9%) on beta-blockers, cough (9%) on ACEI, oedema (18%) on calcium antagonists, dyspnea (9%) on diuretics, dizziness on ARB (8%) and central acting agents (18%). Regression analysis indicates that female patient, uncontrolled BP, age less than 50, and greater number of antihypertensive tablets were independent determinants for at least one side effects under antihypertensive treatments. Season was not a significant determinant of side effect appearance.

This study indicates that during hypertensive treatments, at least one side effect is declared by 40% of patients. A female patient, uncontrolled for BP, aged less of 50 and treated with a multiple therapy is more prone to complain of side effects, but season was not a significant determinant of its appearance.