mavacamten at a glance
Medicine class
Selective, reversible cardiac myosin inhibitor
Licensed use
Symptomatic obstructive hypertrophic cardiomyopathy in adults with NYHA class II–III symptoms
Administration
Swallow the hard capsule whole with water, with or without food
Key monitoring
CYP2C19 testing and regular assessment of heart function by echocardiography
What is mavacamten used for?
The selected UK product is licensed for:
Treating symptomatic obstructive hypertrophic cardiomyopathy in adults whose symptoms are classified as NYHA class II or III.
How does mavacamten work?
Mavacamten reversibly inhibits cardiac myosin, reducing the number of myosin heads producing force. This moderates excessive contraction, improves relaxation and reduces dynamic obstruction to blood flow from the left ventricle.
mavacamten preparations and strengths
Capsule
Route: Oral
Strengths: 2.5 mg, 5 mg, 10 mg, 15 mg
How to take mavacamten
Take mavacamten exactly as directed by the specialist team.
Swallow the capsule whole with water; do not open, crush or chew it.
It may be taken with or without food.
Check with the specialist team or pharmacist before starting, stopping or changing any prescription, non-prescription or herbal product.
Do not stop mavacamten without discussing this with the specialist team.
mavacamten side effects
Common or expected effects
- Dizziness
- Breathlessness
- Fainting
- Reduced left-ventricular pumping function
Get urgent medical advice
- New or worsening breathlessness, chest pain, marked tiredness, palpitations or leg swelling, which may indicate systolic dysfunction or heart failure
- Fainting or collapse
mavacamten in pregnancy
Mavacamten is contraindicated during pregnancy because animal evidence indicates potential harm to the unborn baby. A negative pregnancy test is required before treatment, and effective contraception must be used during treatment and for 6 months after stopping. Anyone who becomes pregnant or plans pregnancy should contact the specialist team immediately.
mavacamten while breastfeeding
It is unknown whether mavacamten enters human milk. Breastfeeding must be avoided during treatment because harmful effects in a breastfed infant cannot be excluded.
mavacamten interactions
Mavacamten has clinically important interactions. The specialist team should review all medicines, including non-prescription and herbal products.
Strong CYP2C19 inhibitor combined with a strong CYP3A4 inhibitor
This combination is contraindicated because it can substantially increase mavacamten exposure and the risk of systolic dysfunction.
Strong CYP3A4 inhibitors, including clarithromycin, itraconazole, ketoconazole, voriconazole, ritonavir and cobicistat
These may increase mavacamten exposure; use is contraindicated when CYP2C19 metabolism is poor or not yet known and otherwise requires specialist review and monitoring.
CYP2C19 inhibitors, including fluconazole, fluvoxamine, fluoxetine, omeprazole and esomeprazole
These can increase mavacamten exposure and heart-failure risk; intermittent use is not recommended and medicine changes require specialist review.
Common questions about mavacamten
Answers are fully visible for fast scanning and source review.
Who is mavacamten licensed to treat in the UK?
It is licensed for adults with symptomatic obstructive hypertrophic cardiomyopathy classified as NYHA class II or III.
Why is a CYP2C19 genetic test needed before mavacamten?
CYP2C19 affects how quickly mavacamten is cleared. Poor metabolisers may develop much higher concentrations and have a greater risk of reduced heart pumping function.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.