Antihypertensive and metabolic effects of concomitant administration of terazosin and methyclothiazide for the treatment of essential hypertension.

The efficacy and safety of once-daily 2.5- or 5.0-mg methyclothiazide (MCTZ) added to once-daily 5.0-mg terazosin (TRZ) versus 5.0-mg TRZ alone was evaluated in this double-blind, multicenter study. All patients received TRZ during a 6-week titration period. Hypertensive patients (222) (mean blood pressure of 159/104 mm Hg) were randomized to one of three treatment groups: TRZ alone (N = 76); TRZ+MCTZ-2.5 mg (N = 74); and TRZ+MCTZ-5.0 mg (N = 72) for the 8-week double-blind period. Changes in the supine and standing SBP/DBP from preTRZ period were: TRZ alone (-4.8/-8.1 and -2.6/-6.1 mm Hg); TRZ+MCTZ-2.5 mg (-17.3/-12.4 and -16.0/-11.2 mm Hg); and TRZ+MCTZ-5.0 mg (-20.6/-14.4 and -23.3/-14.6 mm Hg). Blood pressure changes in the combination groups were significantly greater than those in the TRZ alone group. However, there were no statistically significant differences between the TRZ+MCTZ-2.5-mg and TRZ+MCTZ-5.0-mg groups. The combination of TRZ and MCTZ tends to mitigate the adverse effects on serum glucose, uric, potassium and lipids usually associated with thiazide diuretics. Thus, combination treatment that begins with TRZ and adds MCTZ is effective in lowering blood pressure without any significant adverse metabolic effects.