Which class of antianginal agent should I prescribe in stable angina? Does it matter?

Nitrates
All patients with angina pectoris should have sublingual glyceryl trinitrate (GTN) for the rapid relief of acute pain. Long-acting isosorbide dinitrate (ISDN) and isosorbide mononitrate (ISMN) preparations are also available but have not been shown to influence mortality in post-myocardial infarction (MI) patients.

Beta blockers
In the absence of contraindications, beta blockers are preferred as initial therapy for angina.1 Evidence for this is strongest for patients with prior MI. Long term trials show that there is a 23% reduction in the odds of death among MI survivors randomised to beta blockers.2

Calcium antagonists
Calcium antagonists (especially those which reduce heart rate) are suitable as initial therapy when beta blockers are contraindicated or poorly tolerated. Outcome trials are underway but there is currently little evidence to suggest they improve prognosis post-MI, although diltiazem and verapamil may reduce the risk of reinfarction in patients without heart failure,3 and amlodipine may benefit certain patients with heart failure.

Other agents
Nicorandil, a potassium channel opener with a nitrate moiety, and the metabolic agent, trimetazidine, may also be useful, but these have not been tested in outcome studies. Many patients with exertional symptoms may need a combination of anti-anginals, but there is little evidence to support the use of “triple therapy”. Patients requiring this should be assessed for revascularisation. There are no important differences in the effectiveness of the principal classes of anti-anginal used singly or in combination. Choices should be based on those producing fewest side effects, good compliance and cost effectiveness.