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Antianginal efficacy of carvedilol, a new beta-blocker with vasodilating action
S M Jamal1, S B Freedman, A Thomson
1Hallstrom Institute of Cardiology, University of Sydney, Royal Prince Alfred Hospital, Australia.
Insights
Carvedilol effectively reduces angina symptoms by lowering myocardial oxygen demand. A higher 50 mg dose of this beta-blocker showed superior results compared to 25 mg in improving exercise tolerance and reducing ischemia.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Stable effort angina is a common condition characterized by chest pain during physical exertion.
- Beta-blockers with vasodilating properties are explored for their antianginal potential.
Purpose of the Study:
- To evaluate the antianginal efficacy of carvedilol, a beta-blocker with vasodilating activity.
- To compare the effects of two single doses (25 mg and 50 mg) of carvedilol against a placebo.
Main Methods:
- A randomized, double-blind, placebo-controlled study was conducted.
- Twelve patients with stable effort angina underwent treadmill exercise testing.
- Patients received placebo, carvedilol 25 mg, or carvedilol 50 mg two hours prior to testing.
Main Results:
- Both carvedilol doses reduced resting heart rate; 50 mg also reduced resting blood pressure.
- Carvedilol significantly increased exercise time (24%) and time to angina (35%).
- ST depression was reduced, and the 50 mg dose demonstrated superior efficacy over 25 mg.
Conclusions:
- Carvedilol is effective in preventing and reducing effort angina by decreasing myocardial oxygen demand.
- A significant dose-response relationship was observed, with the 50 mg dose showing greater benefits.
- Carvedilol's dual action as a beta-blocker and vasodilator contributes to its antianginal effects.
Abstract:
To evaluate the antianginal efficacy of carvedilol, a beta-blocker with vasodilating activity, we performed a randomized double-blind placebo-controlled study of two single doses of carvedilol. Twelve patients (eight males, four females, mean age 57 years) with stable effort angina and a positive exercise ECG with angina underwent treadmill exercise testing 2 h after either placebo, or carvedilol 25 or 50 mg. Both doses of carvedilol reduced resting heart rate but only the 50 mg dose reduced resting blood pressure. Exercise time and time to angina increased by 24% and 35%, respectively, after carvedilol, and ST depression at both maximal and submaximal work levels was reduced. The time to 1 mm ST depression was increased by carvedilol but the heart rate at 1 mm ST depression and maximum ST/heart rate slope were unchanged. Maximum heart rate, systolic pressure, and rate-pressure product were significantly reduced by carvedilol. The 50 mg dose was significantly better than 25 mg in prolonging exercise time and reducing subjective and objective measurements of ischemia, and this was related to significantly greater hemodynamic effects. Carvedilol appears to be effective in preventing or reducing effort angina due to reduced myocardial oxygen demand, and it exhibits an important dose-response effect.