Ineffectiveness of practolol induced beta-blockade in the treatment of angina pectoris
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A clinical trial of 7 months duration was carried out on 18 patients with angina pectoris. The study was divided in 4 stages: A 4-week single blind stage on placebo, a six-week single blind, dose finding stage divided in 3 periods of 2 weeks each during which the patients received daily doses of 400, 800 and 1,200 mg of practolol respectively. Physician evaluation based on anginal episodes counts, nitroglycerin consumption and exercise stress testing at the end of each dose period were used to select the optimal dose for each patient. Subsequently and after a 2-week single-blind stage on placebo (wash-out) the patients moved to a fourth stage where the optimal dose of practolol was tested against placebo using a double-blind double cross-over design consisting of 4 periods of 4 weeks each. The patients received practolol during two of these periods and placebo during the other two. No difference between practolol and placebo was seen in the frequency of anginal episodes, the nitroglycerin consumption, the blood pressure level and the exercise performance. A significant difference was observed in the resting heart rate and the exercise heart rate. Thus, although the doses used produced beta-blockade they did not lead to objectively demonstrable antianginal effects.
Key wordsPractolol beta-blockers angina
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