Alpha-adrenergic blockade for variant angina: a long-term, double-blind, randomized trial

Area of Science:

• Cardiology
• Pharmacology

Background:

• Beta-adrenergic blockade may worsen variant angina.
• Alpha-adrenergic blockade theoretically could benefit patients with variant angina.

Purpose of the Study:

• To evaluate the efficacy of prazosin, an alpha-adrenergic blocking agent, in patients with variant angina.

Main Methods:

• A double-blind, randomized, double-crossover trial comparing prazosin to placebo in six male patients with variant angina.
• The trial lasted 4 1/2 months, including an initial open-label prazosin period followed by alternating blinded therapy.
• Patients received prazosin at 14.0 +/- 2.4 mg/day; no other vasoactive medications were used.

Main Results:

• Prazosin significantly reduced systolic arterial pressure (145 to 127 mm Hg, p = 0.02) but did not affect diastolic pressure or heart rate.
• No significant differences were observed in weekly chest pain episodes, nitroglycerin use, or transient ST-segment deviations between prazosin and placebo.
• Adverse effects included orthostatic dizziness in three patients and headache in one.

Conclusions:

• Long-term randomized trial indicates prazosin offers no apparent benefit for variant angina.
• Alpha-adrenergic blockade with prazosin is not effective in managing variant angina symptoms or objective measures.