Ivabradine, marketed under trade names including Coralan, Corlentor, Procoralan, Coraxan, and many more, is a medication used for the symptomatic management of stable heart-related chest pain and heart failure not fully managed by beta blockers. Ivabradine acts by reducing the heart rate via specific inhibition of the pacemaker current, a mechanism different from that of beta blockers and calcium channel blockers, two commonly prescribed antianginal drugs. Ivabradine is a cardiotonic agent.
It may be as effective as the beta blockeratenolol and comparable with amlodipine in the management of chronic stable angina.
Heart failure
It is used in combination with beta blockers in people with heart failure with LVEF lower than 35 percent inadequately controlled by beta blockers alone and whose heart rate exceeds 70 beats per minute. In people not sufficiently managed with beta blockers for their heart failure adding ivabradine decreases the risk of hospitalization for heart failure.
Tachycardia
It can be used as a bradycardic agent as it has shown to inhibit the If current.
Overall, 14.5% of patients taking ivabradine experience luminous phenomena. This is probably due to blockage of Ihion channels in the retina, which are very similar to cardiac If. These symptoms are mild, transient, and fully reversible. In clinical studies, about 1% of all patients had to discontinue the drug because of these sensations, which occurred on average 40 days after the drug was started. In a large clinical trial, bradycardia occurred in 2% and 5% of patients taking ivabradine at doses of 7.5 and 10 mg respectively. 2.6–4.8% reported headaches. Other common adverse drug reactions include first-degree AV block, ventricular extrasystoles, dizziness and/or blurred vision.
Mechanism of action
Ivabradine acts on the If ion current, which is highly expressed in the sinoatrial node. If is a mixed Na+–K+ inward current activated by hyperpolarization and modulated by the autonomic nervous system. It is one of the most important ionic currents for regulating pacemaker activity in the sinoatrial node. Ivabradine selectively inhibits the pacemaker If current in a dose-dependent manner. Blocking this channel reduces cardiac pacemaker activity, selectively slowing the heart rate and allowing more time for blood to flow to the myocardium. This is in contrast to other commonly used rate-reducing medications, such as beta-blockers and calcium channel blockers, which not only reduce heart rate, but also the cardiac contractility. Given the selective decrease in rate without loss of contractility, ivabradine may prove efficacious for treatment of congestive heart failure with reduced ejection fraction. Ivabradine binds to HCN4 receptors, utilizing Y506, F509 and I510 residues.
Clinical trials
Coronary artery disease
The BEAUTIFUL study randomised over 10917 patients having stable coronary artery disease and left ventricle dysfunction. Ivabradine did not show a significant reduction in the primary composite endpoint of cardiovascular death, admission to hospital for acute myocardial infarction, and admission to hospital for new onset or worsening heart failure. However, in a prespecified subgroup of patients with a heart rate of more than 70 bpm, ivabradine significantly reduced the following secondary endpoints:
Coronary events by 22%
Fatal and nonfatal myocardial infarction by 36%
Coronary revascularization by 30%.
The SIGNIFY trial randomized 19,102 patients with coronary artery disease and a heart rate greater than 70, but without clinical heart failure to ivabradine or placebo in addition to standard therapy. Ivabradine did not improve outcomes in this patient group.
Chronic heart failure
In the SHIFT study, ivabradine significantly reduced the risk of the primary composite endpoint of hospitalization for worsening heart failure or cardiovascular death by 18% compared with placebo on top of optimal therapy. These benefits were observed after 3 months of treatment. SHIFT also showed that administration of ivabradine to heart failure patients significantly reduced the risk of death from heart failure by 26% and hospitalization for heart failure by 26%. The improvements in outcomes were observed throughout all prespecified subgroups: female and male, with or without beta-blockers at randomization, patients below and over 65 years of age, with heart failure of ischemic or non-ischemic etiology, NYHA class II or class III, IV, with or without diabetes, and with or without hypertension. A note of caution must be emphasised. Ivabradine, though indicated for chronic heart failure in patients who are clinically stable, is not indicated in acute heart failure where the enhanced heart rate represents cardiac reserve. Indiscriminate use of Ivabradine could destabilise these patients.
It is marketed by Amgen under the trade name Corlanor in the United States, and by Servier in the rest of the world under the trade names Procoralan, Coralan, Corlentor, Lancora and Coraxan. It is also marketed in India under the brand names Ivabrad, Ivabid, IVAMAC and Bradia. During its development, ivabradine was known as S-16257.