Diltiazem dose responses in sustained therapy for stable angina pectoris

Area of Science:

• Cardiology
• Pharmacology

Background:

• Stable effort angina is a common condition characterized by chest pain during physical exertion.
• Diltiazem, a calcium channel blocker, is used to manage angina by improving myocardial oxygen supply and demand.
• Understanding the long-term effects of diltiazem on exercise tolerance is crucial for optimizing patient treatment.

Purpose of the Study:

• To evaluate the efficacy of different doses of diltiazem in reducing angina frequency and nitroglycerin consumption.
• To assess the impact of sustained diltiazem treatment on exercise performance and hemodynamic responses.
• To investigate the relationship between plasma diltiazem levels and exercise tolerance.

Main Methods:

• A double-blind, placebo-controlled, crossover study involving 15 patients with stable effort angina.
• Patients received diltiazem (120 mg, 240 mg, 360 mg) or placebo for 2 weeks each.
• Exercise treadmill testing and hemodynamic monitoring were performed at various time points after drug administration and during sustained therapy.

Main Results:

• Diltiazem significantly decreased angina frequency and nitroglycerin consumption in a dose-dependent manner.
• Sustained diltiazem therapy did not alter the exercise performance response to a single 120 mg dose of diltiazem.
• Hemodynamic changes indicated reduced myocardial oxygen demand and increased supply, with no attenuation of response during sustained therapy.

Conclusions:

• Diltiazem is effective in managing stable effort angina, reducing symptoms and medication use.
• Long-term diltiazem treatment does not impair the acute exercise-induced benefits of the drug.
• Plasma diltiazem levels did not correlate with exercise tolerance, suggesting other factors may influence response.