Ivabradine
Other antianginals
Other antianginals
A heart-rate-lowering drug that blocks the sinus node's pacemaker current. Used in heart failure and angina when the patient is in sinus rhythm.
Quick facts
- Group
- Other antianginals
- Target
- HCN4 channel of the sinoatrial node (If current)
- Used for
- Chronic stable angina
- Key effects
- Bradycardia · Luminous phenomena · High blood pressure
- Monitor
- Resting heart rate and symptoms · Heart rhythm
- ATC
- C01EB17
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows ivabradine bound in the pore of the rabbit HCN4 channel, very similar to the human channel.
Ivabradine blocks HCN channels that carry the 'funny' current If, which drives diastolic depolarisation in the sinoatrial node. The slope of depolarisation falls and the sinus rate slows, without effect on contractility or ventricular repolarisation. It also partly blocks the related Ih current of the retina, which explains the luminous phenomena.
- Ivabradine enters and blocks HCN4 channels in the sinus node
- The If current falls and diastolic depolarisation slows
- Heart rate falls without loss of contractility
Indications
- Stable symptomatic chronic heart failure with reduced ejection fraction, in sinus rhythm with a raised resting heart rate despite beta blockers (or when they cannot be used) Heart failure →
- Chronic stable angina in sinus rhythm when beta blockers are not tolerated or not enough (used outside the US; not a US labelled indication) Stable angina →
Adverse effects
Common
- Bradycardia
- Luminous phenomena (phosphenes): brief brighter areas in the visual field
- High blood pressure
Contraindications
- Acute decompensated heart failure
- Clinically significant hypotension or bradycardia
- Sick sinus syndrome, sinoatrial block or third-degree AV block without a working demand pacemaker
- Heart rate set entirely by a pacemaker
- Severe liver impairment
- Strong CYP3A4 inhibitors
Key interactions
- Strong CYP3A4 inhibitors (azole antifungals, clarithromycin, HIV protease inhibitors)
- Much higher ivabradine levels and bradycardia; contraindicated
- Diltiazem, verapamil and grapefruit juice
- Higher levels plus extra heart-rate slowing; avoided
- CYP3A4 inducers (rifampicin, phenytoin, barbiturates, St John's wort)
- Lower ivabradine levels
- Beta blockers, digoxin, amiodarone
- Additive bradycardia; heart rate is monitored
What is monitored
- Resting heart rate and symptoms of bradycardia
- Heart rhythm, watching for atrial fibrillation
- Blood pressure
Administration and safety
- Taken with meals.
- Requires sinus rhythm: it does not slow the ventricle in atrial fibrillation.
Pregnancy and breastfeeding
Animal studies showed fetal toxicity and heart malformations, so effective contraception is used and it is avoided in pregnancy.
Nursing care
- Count the resting pulse before doses and report bradycardia, dizziness or fatigue.
- Ask about palpitations or an irregular pulse (atrial fibrillation).
- Teach that brief light flashes may occur, especially with sudden changes in brightness, and to take care when driving at night.
- Teach women who could become pregnant to use effective contraception and to avoid grapefruit juice.
Pharmacokinetics
- Absorption
- Taken with food, which delays absorption and increases exposure
- Metabolism
- Extensively by CYP3A4 in liver and gut, to an active metabolite
Test yourself
Think of the answer, then tap the question to see it.
What are the luminous phenomena caused by ivabradine and why do they occur?
Brief bright areas in the visual field; ivabradine partly blocks the Ih current of retinal cells.
Why must the patient be in sinus rhythm for ivabradine to work?
It slows only the sinus node pacemaker; in atrial fibrillation the ventricular rate depends on the AV node.
Which drug group is contraindicated with ivabradine because of metabolism?
Strong CYP3A4 inhibitors such as azole antifungals and clarithromycin.
How does ivabradine lower heart rate differently from a beta blocker?
It blocks the If pacemaker current directly, without lowering contractility or blood pressure.
Connections
← Back to the class: Other antianginals
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - IVABRADINE tablet, film coated (DailyMed (U.S. National Library of Medicine), 2026); Ivabradine: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); 8OFI: Ivabradine bound to HCN4 channel (RCSB Protein Data Bank, 2024).
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Representative model, for educational purposes only.