Tolerability of antihypertensive drugs in a community-based setting.

Background: Outside the experimental environment of clinical trials, the tolerability of angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), and the angiotensin II antagonist losartan has not been compared.

Objectives: The purpose of this study was to estimate, in current clinical practice, the 3-month cumulative incidence of side effects among first-time users of losartan, ACEIs, and CCBs for hypertension.

Methods: We conducted a prospective cohort study through a network of 173 pharmacies across Canada to identify patients with hypertension who were newly prescribed monotherapy with losartan, an ACEI, or a CCB. Individuals were interviewed by telephone 3 times over a 3-month period to determine perceived side effects of the antihypertensive medication prescribed. Data were analyzed using a multivariate logistic regression model.

Results: Among the 663 eligible individuals, the 3-month cumulative incidence of perceived side effects was 52.5% (42/80), 60.2% (222/369), and 69.6% (149/214) for those treated with losartan, an ACEI, and a CCB, respectively. After adjustment for sex, age, level of education, number of symptoms perceived the week before entering the study, prior use of antihypertensive drugs, current use of any other drug, drug insurance coverage, and duration of hypertension, the odds of reporting a side effect were significantly higher among patients treated with an ACEI (odds ratio [OR] = 1.78: 95% CI, 1.02-3.12) or a CCB (OR = 2.65; 95% CI, 1.47-4.78) compared with patients treated with losartan.

Conclusions: In a community-based setting, we observed that losartan is better tolerated than ACEIs and CCBs. Given that the occurrence of side effects may contribute to lower adherence to drug treatment, the low incidence of side effects associated with losartan makes it an attractive antihypertensive drug choice.