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# Other antianginals

Antianginals outside the nitrate, beta blocker and calcium channel blocker groups: ivabradine slows the sinus node; ranolazine blocks the late sodium current.

Updated Nov 1, 2026

## What they are

Second-line drugs added when angina or heart failure persists despite standard treatment, or when standard drugs are not tolerated. Ivabradine (If channel blocker) slows the heart rate without lowering blood pressure or contractility; ranolazine (late sodium current blocker) reduces angina without changing heart rate or blood pressure; trimetazidine shifts myocardial metabolism from fatty acids to glucose.

## Mechanism of action

Ivabradine blocks HCN channels of the sinoatrial node, which carry the 'funny' pacemaker current If, so diastolic depolarisation is slower and the heart rate falls. Ranolazine inhibits the late inward sodium current; less sodium loading means less calcium overload through the sodium-calcium exchanger in ischaemic cells. Trimetazidine inhibits long-chain 3-ketoacyl-CoA thiolase in fatty acid beta-oxidation.

Target: HCN4 channel (If current), cardiac late sodium current (Nav1.5), 3-ketoacyl-CoA thiolase

## Key points

- Ivabradine needs sinus rhythm to work; it is useless in atrial fibrillation and can itself raise the risk of atrial fibrillation.
- Luminous phenomena (phosphenes) with ivabradine come from block of the related Ih current in the retina.
- Ranolazine prolongs the QT and is contraindicated with strong CYP3A inhibitors, CYP3A inducers and liver cirrhosis.
- Both ivabradine and ranolazine depend on CYP3A4: azoles, macrolides, diltiazem, verapamil and grapefruit raise their levels.

## Drugs in this class

- [**Ivabradine** A heart-rate-lowering drug that blocks the sinus node's pacemaker current. Used in heart failure and angina when the… HCN4 channel of the sinoatrial node (If current)](https://durgical.com/en/pharmacology/ivabradine/)
- [**Ranolazine** A chronic angina drug that blocks the late sodium current. It reduces angina without changing heart rate or blood… Cardiac sodium channel Nav1.5 (late sodium current)](https://durgical.com/en/pharmacology/ranolazine/)
- [**Trimetazidine** A metabolic antianginal that shifts heart energy use from fatty acids to glucose. Add-on for stable angina; avoided in… Long-chain 3-ketoacyl-CoA thiolase (mitochondrial)](https://durgical.com/en/pharmacology/trimetazidine/)

## Others in the class

- Trimetazidine
- Nicorandil

## Test yourself

Think of the answer, then tap the question to see it.

## Which current does ivabradine block and where?

The If 'funny' current carried by HCN channels in the sinoatrial node.

## Why does ivabradine not help a patient in atrial fibrillation?

It acts only on the sinus node pacemaker; in atrial fibrillation the ventricular rate is set by the AV node.

## Which antianginal reduces angina without changing heart rate or blood pressure?

Ranolazine, which blocks the late sodium current and limits calcium overload in ischaemic myocytes.

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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](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=676907d3-b374-4baa-8422-c04706409540) (DailyMed (U.S. National Library of Medicine), 2026); [DailyMed - RANOLAZINE tablet, extended release](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d74f3dea-7357-4e9a-be9a-2f498a44108a) (DailyMed (U.S. National Library of Medicine), 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/classes/other-antianginals/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/other-antianginals/