Camzoy 5

Indications

Mavacamten is used in adults to treat symptomatic obstructive hypertrophic cardiomyopathy (HCM) of moderate severity. HCM is an inherited condition in which the heart muscle becomes thick and squeezes too hard, partly blocking blood flow out of the heart. Mavacamten helps improve breathlessness, chest discomfort, tiredness and exercise ability.

How It Works

Mavacamten is a cardiac myosin inhibitor. Myosin is the protein in heart muscle that pulls to make each heartbeat. In HCM too many myosin units are active at once. Mavacamten reduces this extra activity, so the heart squeezes less forcefully and relaxes better. This lowers the blockage to outflow and the pressure inside the heart.

Dosage and Administration

This is a specialist medicine. Take it exactly as prescribed by a cardiologist, once daily, with or without food. The dose is adjusted step by step based on regular echocardiograms (heart ultrasound) and on other medicines you take. Do not change the dose or start or stop other medicines without telling your heart specialist.

Interactions

• Many medicines change Mavacamten levels through liver enzymes (CYP2C19 and CYP3A4). Omeprazole, Esomeprazole, Fluconazole, Fluvoxamine, Ketoconazole, Clarithromycin and some HIV medicines can raise levels and the risk of heart failure.
• Rifampicin, Carbamazepine, Phenytoin and St John's Wort can lower levels and reduce effect.
• It can reduce the effect of hormonal contraceptives.
• Other medicines that weaken heart contraction, such as Disopyramide, need careful monitoring.

Contraindications

• Allergy to Mavacamten.
• Pregnancy.
• Use with strong CYP3A4 inhibitors or with strong CYP2C19 or CYP3A4 inducers listed by the doctor.
• Starting when the heart pumping strength (ejection fraction) is already below the level set by the specialist.

Side Effects

Possible effects include dizziness, fainting, and, in some people, a fall in heart pumping strength that can lead to heart failure.

Get urgent medical help if you have new or worse shortness of breath, swelling of the legs, rapid weight gain, a fast or pounding heartbeat, chest pain, or fainting. Also tell your doctor straight away if you develop a serious infection or an irregular heartbeat, as these can increase the risk of heart failure.

Pregnancy and Lactation

Mavacamten may harm an unborn baby. Women who can become pregnant need a pregnancy test before starting and must use effective contraception during treatment and for several months after stopping; a non hormonal method or an added barrier method is advised. It is not known if it passes into breast milk; breastfeeding is generally not recommended.

Precautions and Warnings

• Regular echocardiograms are required.
• Tell every doctor and pharmacist that you take Mavacamten before starting any new medicine, including acid reducers and herbal products.
• Illness with fever, or new heart rhythm problems, may need a pause in treatment.

Overdose

Overdose may cause a strong drop in heart function, low blood pressure and fainting. Seek emergency medical care immediately.

Therapeutic Class

Cardiac myosin inhibitor.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.