Dronedarone
Antiarrhythmics
AntiarrhythmicsPregnancy: avoid
Avoided in pregnancy: it may harm the fetus, so effective contraception is used and breastfeeding is avoided.
An amiodarone relative without iodine that helps keep sinus rhythm after atrial fibrillation. Dangerous in severe heart failure or permanent AF.
Quick facts
- Group
- Antiarrhythmics
- Target
- Cardiac potassium (hERG/IKr and others), sodium and L-type calcium channels; also beta-adrenergic receptors
- Key effects
- Diarrhoea · Weakness · Rash and skin redness
- Monitor
- ECG regularly · Liver tests
- ATC
- C01BD07
No doses: the clinician sets them by the current guideline.
Mechanism of action
Dronedarone is a benzofuran derivative of amiodarone without iodine atoms and with a sulfonyl group that makes it less fat-soluble. Like amiodarone it blocks several cardiac potassium currents (prolonging repolarisation, a class III effect), sodium and L-type calcium channels, and beta-adrenergic receptors. This lengthens the atrial refractory period, slows the sinus rate and AV conduction, and helps keep sinus rhythm. Lacking iodine, it causes fewer thyroid problems, but it is less effective than amiodarone.
- Blocks K+ channels: longer repolarisation (class III)
- Also blocks Na+ and Ca2+ channels and beta receptors
- Longer atrial refractory period; slower AV conduction
- Fewer recurrences of atrial fibrillation
Indications
- To reduce hospitalisation for atrial fibrillation in patients with paroxysmal or persistent AF who are back in sinus rhythm Atrial fibrillation →
Adverse effects
Common
- Diarrhoea, heartburn, nausea
- Weakness
- Rash and skin redness
- Slow heart rate
Contraindications
- Severe or recently decompensated heart failure
- Permanent atrial fibrillation (sinus rhythm cannot be restored)
- Liver or lung toxicity with previous amiodarone
- Long QT, marked bradycardia or other conduction disease without a pacemaker
Key interactions
- Grapefruit juice
- Raises dronedarone levels; avoided.
- St John's wort
- Lowers dronedarone levels; avoided.
- Other QT-prolonging drugs
- Added QT prolongation and torsades risk.
What is monitored
- ECG regularly (at least every few months) to confirm sinus rhythm; it is stopped if AF becomes permanent
- Liver tests, especially in the first months
- Symptoms of heart failure and breathlessness
- Other laboratory tests as ordered
Administration and safety
- Oral tablet twice daily with the morning and evening meals.
- Not taken with grapefruit juice.
- Every new prescription is checked for CYP3A4 and QT interactions.
Pregnancy and breastfeeding
Avoided in pregnancy: it may harm the fetus, so effective contraception is used and breastfeeding is avoided.
Nursing care
- Before: confirm sinus rhythm, record weight and check liver and kidney tests.
- During: teach to report breathlessness, swelling or sudden weight gain at once.
- Teach the signs of liver injury (yellow skin, dark urine, pale stools).
- Check pulse; report a slow or irregular rate.
Pharmacokinetics
- Absorption
- Oral; taken with the morning and evening meals.
- Metabolism
- Liver, by CYP3A4; grapefruit raises its levels.
Test yourself
Think of the answer, then tap the question to see it.
How does dronedarone differ structurally from amiodarone?
It lacks iodine and has a sulfonyl group, so it causes fewer thyroid problems and is less fat-soluble.
In which two situations does dronedarone raise mortality?
Severe or recently decompensated heart failure, and permanent atrial fibrillation.
Which fruit juice must be avoided with dronedarone, and why?
Grapefruit juice: it inhibits CYP3A4 and raises dronedarone levels.
Connections
← Back to the class: Antiarrhythmics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Dronedarone: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2018); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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