A cardiac myosin inhibitor for obstructive hypertrophic cardiomyopathy
Aficamten
A specialist heart medicine that reduces excessive heart-muscle contraction in obstructive hypertrophic cardiomyopathy.
What is Aficamten?
Aficamten is a specialist medicine for obstructive hypertrophic cardiomyopathy, a condition where the heart muscle is thickened and squeezes too hard, blocking blood leaving the heart. It works by gently dialling back how forcefully the heart contracts, which eases the obstruction and improves breathlessness and exercise ability. Because it lowers the heart's pumping strength, it can reduce the heart's function too much and bring on heart failure, so it is started carefully and the heart is checked regularly with an echocardiogram (a heart ultrasound). It is taken by mouth under close specialist supervision.
Education and reference only. This is a plain-language guide to Aficamten — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Aficamten is a cardiac myosin inhibitor, a type of heart medicine used in obstructive hypertrophic cardiomyopathy. In this condition the heart muscle is abnormally thick and contracts too forcefully, which can obstruct the flow of blood out of the heart and cause breathlessness, chest discomfort and reduced exercise tolerance. Aficamten works directly on the heart muscle to reduce this excessive contraction. It is taken by mouth and is a specialist treatment, started and supervised by a cardiology team with regular heart scans to make sure it is working safely.
How it works
Aficamten acts on myosin, one of the proteins the heart muscle uses to contract. By reducing how many of these contracting units are active at once, it lowers how forcefully the heart squeezes. In obstructive hypertrophic cardiomyopathy this eases the obstruction to blood leaving the heart, so blood flows more freely and symptoms such as breathlessness improve. Because the same effect can dampen the heart's pumping more than intended, the dose is adjusted gradually and guided by regular echocardiograms that measure how well the heart is functioning.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist heart medicine used in the UK for obstructive hypertrophic cardiomyopathy, prescribed and monitored by cardiology teams.
Practical use
How to take Aficamten
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth as prescribed, at about the same time each day, exactly as your cardiology team directs.
- Attend all your echocardiogram (heart scan) appointments, as these guide whether the dose is safe and right for you.
- Report new or worsening breathlessness, ankle swelling, dizziness or fainting promptly.
- Give your team a full list of your other medicines, as several can change how aficamten works.
- Do not stop or change the dose without specialist advice, as this can affect your heart.
Weighing it up
Advantages & disadvantages of Aficamten
Advantages
- Targets the underlying problem in obstructive hypertrophic cardiomyopathy by easing excessive heart-muscle contraction.
- Can improve breathlessness and exercise ability and reduce the obstruction to blood leaving the heart.
- Taken by mouth, offering a medicine-based option that may reduce the need for some procedures.
Disadvantages
- Can reduce the heart's pumping strength too much and bring on heart failure if not carefully monitored.
- Requires regular echocardiograms and close specialist supervision.
- Interacts with a number of other medicines, so careful review is needed.
Practical use
Good to know
The most important thing to understand about aficamten is that it deliberately reduces how hard the heart pumps, so there is a balance to strike: too much effect can weaken the heart's function and bring on heart failure. For this reason the cardiology team starts it carefully, adjusts the dose slowly, and arranges regular echocardiograms (heart ultrasound scans) to measure heart function and the obstruction. You should report new or worsening breathlessness, swelling of the ankles, dizziness or fainting promptly. It also interacts with a number of other medicines that change how the body handles it, so a full medicines list is essential. It is a long-term treatment that needs to be taken consistently and reviewed regularly, and it should not be stopped or changed without specialist advice.
Who should not take it / use with caution
- People who have had a serious allergic reaction to aficamten should not take it.
- It is not suitable for people whose heart pumping function is already too low, as it can worsen it.
- It is used with caution alongside medicines that strongly change how the body handles it, under specialist guidance.
- It is used with care in pregnancy and breastfeeding, with the specialist weighing benefits and risks.
Monitoring
- Regular echocardiograms (heart ultrasound scans) to check the heart's function and the obstruction.
- Reviewing symptoms such as breathlessness, dizziness and exercise ability.
- Adjusting the dose carefully over time based on the scans and how you feel.
Side effects
- A reduction in the heart's pumping function, which monitoring is designed to catch.
- Dizziness, faintness or worsening breathlessness in some people.
- Tiredness, palpitations or, less commonly, swelling of the ankles.
Key interactions
- Medicines that change how the liver breaks down aficamten can raise or lower its levels, so a full medicines list is important.
- Other heart medicines that reduce pumping strength may add to its effect and need careful review.
- Tell your team about all medicines, including those bought over the counter, before starting.
Available as: Tablets taken by mouth.
Answers
Aficamten: frequently asked questions
What is aficamten used for?
It is used to treat obstructive hypertrophic cardiomyopathy, easing the excessive heart-muscle contraction that blocks blood leaving the heart and causes breathlessness.
Why do I need regular heart scans?
Aficamten reduces how hard the heart pumps, so regular echocardiograms check that it is not lowering the heart's function too much, which guides the dose.
Can it cause heart failure?
Yes, if it reduces the heart's pumping too much it can bring on heart failure, which is why it is started carefully and monitored closely; report worsening breathlessness or swelling promptly.
Why does my team need my full medicines list?
Several medicines change how the body handles aficamten or add to its effect on the heart, so a complete list helps keep treatment safe.
Can I stop it if I feel better?
No. It is a long-term treatment, and stopping or changing it without specialist advice can affect your heart, so only adjust it on their guidance.
Authoritative sources
- BNF
- NICE CKS
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