Postmarketing study of timolol-hydrochlorothiazide antihypertensive therapy.

A postmarketing surveillance study was conducted to determine the safety and efficacy of a fixed-ratio combination containing 10 mg of timolol maleate and 25 mg of hydrochlorothiazide, administered twice daily for one month to hypertensive patients. Data on 9,037 patients were collected by 1,455 participating physicians. Mean systolic blood pressure decreased 25 mmHg and mean diastolic blood pressure declined 15 mmHg after one month of timolol-hydrochlorothiazide therapy (P less than 0.01, both comparisons). Age, race, and sex appeared to have no influence on the decrease in blood pressure. The antihypertensive effect of the drug was greater in patients with more severe hypertension. Overall, 1,453 patients experienced a total of 2,658 adverse events, the most common being fatigue, dizziness, and weakness. Treatment in 590 patients was discontinued because of adverse events.