Ivabradine: new drug. Best avoided in stable angina.

(1) The first-line symptomatic treatment for stable angina is a betablocker such as atenolol. Some calcium channel blockers such as verapamil, and the potassium channel agonist amlodipine, are second-line alternatives. Long-acting nitrate derivatives have poorly documented efficacy but can be used as adjuvants or as third-line treatments. (2) Ivabradine is derived from verapamil but appears to have a different mechanism of action, mainly lowering the heart rate. It was approved for sale in Europe through the centralised procedure for second-line treatment of stable angina. (3) Clinical evaluation of ivabradine only includes randomised controlled trials versus two other anti-angina drugs: atenolol and amlodipine. Three double-blind randomised controlled trials lasting 3 to 4 months, based on surrogate exercise endpoints, failed to show that ivabradine was any more effective than atenolol or amlodipine, or even more effective than placebo in patients already treated with amlodipine. (4) In two one-year double-blind randomised controlled trials comparing ivabradine with atenolol or amlodipine in a total of 704 patients, ivabradine was no more effective than the comparators in preventing angina attacks. (5) In head-to-head comparisons, serious coronary events were significantly more frequent with ivabradine than with atenolol (3.8% versus 1.5%). Severe arrhythmias were also more frequent with ivabradine than with atenolol (1.3% versus 0.7%) or amlodipine (0.6% versus 0.2%). (6) Ivabradine provokes phosphenes (flashing lights, etc.) in about 17% of patients in the short term. Information is inadequate to assess possible risks of retinal toxicity in the long term. (7) Ivabradine is metabolised by cytochrome P450 isoenzyme CYP 3A4; there is therefore a potentially high risk of pharmacokinetic interactions. (8) In practice, for long-term preventive treatment of angina it is better to avoid ivabradine and to use better-documented treatments: preferably a betablocker, or, if a betablocker cannot be used, verapamil or amlodipine.