Other antianginal drugs
Stable angina usually results from atherosclerotic plaques in the coronary arteries. This restricts blood flow and oxygen supply to the heart. Stable angina is often precipitated by exertion and relieved by rest.
Stable angina medications include nitrates (the drugs of choice), calcium-channel blockers (CCBs), beta-blockers and potassium channel activators. These drug families have vasodilatory effects which reduce blood pressure. Arteriolar dilatation reduces peripheral vascular resistance and left ventricular pressure during systole resulting in improved cardiac output.
In patients with intolerance of, or contra-indication to, either nitrates, beta-blockers or CCBs, the drugs listed below can be used as alternative antianginal medications.
Potassium channel activators:
Nicorandil: a potassium-channel activator with a nitrate component, with both arterial and venous vasodilating properties. Approved for the prevention and long-term treatment of angina.
Drugs with 'other' mechanisms of action :
Ivabradine: Ivabradine inhibits the If ion current (a mixed Na+–K+ inward current activated by hyperpolarization and modulated by the autonomic nervous system) in the sinoatrial node (cardiac pacemaker) (PMID: 15301560). Heart rate is reduced without any negative effects on myocardial contractility or ventricular repolarization. Oral ivabradine is indicated for angina patients in normal sinus rhythm, and for those with mild to severe chronic heart failure. Contra-indicated in acute myocardial infarction or slow heart rate (<70bpm), immediately after cerebrovascular accident, patients dependent on pacemaker, second- and third-degree heart block, severe hypotension, sick-sinus syndrome, sino-atrial block, unstable angina or unstable or acute heart failure. Common side-effects include atrial fibrillation, blurred vision, bradycardia, dizziness, first-degree heart block, headache, phosphenes, ventricular extrasystoles and visual disturbances.
Ranolazine: Likely to act via cardiac sodium channels to modulate sodium ion permeability and cellular excitability. Indicated as an adjunctive therapy in the treatment of stable angina in patients inadequately controlled or intolerant of first-line antianginal therapies. Caution should be exercised in patients with low body weight, moderate to severe congestive heart failure, QT interval prolongation and in the elderly. Avoid use in patients with moderate and severe hepatic or renal impairment.Common side-effects include asthenia, constipation, dizziness, headache, nausea and vomiting.