Anti-Hypertensive Effect of Timolol, a New Beta-Blocking Agent (Double-Blind Study)

Abstract

The anti-hypertensive effect of timolol maleate (MK-950) was evaluated in patients with mild or moderate hypertension, in a double-blind, randomized, placebo controlled clinical trial. The study was divided into a baseline placebo period, that lasted 9 weeks, during which documentation was made of the patient's untreated diastolic blood pressure. A 9 week titration period followed the placebo period, at which time patients were randomly assigned to an MK-950 or matching placebo group; the titration period was devoted to finding out the optimal dose of MK-950 or its matching placebo. The titration period was followed by a 6 week maintenance period during which patients were maintained on their optimal MK-950 or placebo dose. Timolol is an effective anti-hypertensive drug and significantly reduces diastolic blood pressure. Its effect becomes apparent at the first week of treatment, and reaches maximum effectiveness at 4 weeks of treatment. The diastolic blood pressure in the timolol group remained consistently below 90 mm Hg and at the end of the study, the average diastolic blood pressure was: 88·57 ± 8·6 mm Hg (p > 0·001 in comparison with placebo). The average daily dose of timolol maleate was 31·10 ± 1·80 mg. MK-950 has a strong negative chronotropic effect, capable of reducing the resting heart rate by an average of 28·50 beats/min. No correlation could be established between heart rate and blood pressure lowering effect. Other than bradycardia, no important side-effects were observed.