LOW-DOSE BISOPROLOL HYDROCHLOROTHIAZIDE - AN OPTION IN 1ST-LINE, ANTIHYPERTENSIVE TREATMENT

Two recent, multicenter, double-blind, placebo-controlled studies esta blished the efficacy and safety of low-dose bisoprolol/hydrochlorothia zide (HCTZ) in patients with mild to moderate essential hypertension. Bisoprolol, a cardioselective beta-blocker, was used in a dose of 2.5 mg, 5 mg, or 10 mg. HCTZ was used at a dose of 6.25 mg. This low-dose compound was developed to minimize dose-related adverse effects. The a ddition of HCTZ to each of the doses of bisoprolol was compared with m onotherapy and placebo. Results of both studies demonstrated that this once-a-day, low-dose option effectively reduced sitting diastolic and systolic blood pressure measured at the end of the 24-hour dosing per iod. Drug-related adverse effects, including those generally associate d with traditional beta-blocker therapy, were infrequent in individual s who received the low-dose bisoprolol/HCTZ regimen. Dose-related side effects were minimized because of the low doses of the two agents use d together. There were no significant changes in mean total cholestero l, triglycerides, or serum glucose with bisoprolol/HCTZ 6.25 mg therap y versus placebo (analysis of variance statistical methods). The incid ence of treatment-induced hypokalemia with bisoprolol/HCTZ 6.25 mg was not significant; uric acid elevations were minimized, and the inciden ce of hyperuricemia was significantly (P<0.01) less with bisoprolol/HC TZ 6.25 mg than with 25 mg of HCTZ. Once-a-day dosing with the low-dos e agent controlled (defined as a sitting diastolic blood pressure less -than-or-equal-to 90 mmHg and/or a decrease from baseline greater-than -or-equal-to 10 mmHg) blood pressure in up to 80% of patients for a fu ll 24 hours after dosing. The incidence of adverse effects was similar to placebo for each of the bisoprolol/HCTZ 6.25 mg groups and when al l three groups were combined. It was concluded that this new treatment regimen of bisoprolol plus 6.25 mg of HCTZ may be a valid option for first-line treatment of mild to moderate hypertension.