Mavacamten Side Effects

Medically reviewed by Drugs.com. Last updated on Nov 4, 2023.

Applies to mavacamten: oral capsule.

Precautions

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

You should not use this medicine together with diltiazem (Cardizem®) with a beta blocker, disopyramide (Norpace®), ketoconazole (Nizoral®), ranolazine (Ranexa®), rifampin (Rifadin®), or verapamil (Isoptin®) with a beta blocker. Using these medicines together with mavacamten may increase the risk of heart rhythm problems and heart failure.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may give you a pregnancy test before you start using this medicine to make sure you are not pregnant. Use an effective form of birth control during treatment with this medicine and for at least 4 months after the last dose. If you think you have become pregnant while using the medicine, tell your doctor right away.

This medicine may increase your risk of heart failure. Check with your doctor right away if you have chest pain or tightness, decreased urine output, dilated neck veins, irregular breathing, irregular heartbeat, swelling of the face, fingers, feet, or lower legs, trouble breathing, unusual tiredness or weakness, or weight gain.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of mavacamten

Along with its needed effects, mavacamten may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking mavacamten:

For healthcare professionals

Applies to mavacamten: oral capsule.

General adverse events

The most common adverse reactions reported in more than 5% of patients were dizziness and syncope.

Cardiovascular

• Common (1% to 10%): Reduced left ventricular ejection fraction (LVEF), atrial fibrillation, palpitations, angina pectoris, heart failure, systolic dysfunction
• Frequency not reported: Reduced systolic contraction^[Ref]

In a clinical trial, mean resting LVEF was 74% at baseline in patients treated with this drug and those treated with placebo. Mean absolute change from baseline in LVEF was 4% with this drug and 0% with placebo over the 30-week treatment period. At Week 38 (after an 8-week interruption of trial drug), mean LVEF was similar to baseline for both treatment groups. In the clinical trial, 7 patients (6%) taking this drug and 2 patients (2%) taking placebo had reversible reductions in LVEF to less than 50% (median: 48%; range: 35% to 49%) during therapy; in 3 of the 7 patients taking this drug and 1 of the 2 placebo patients taking placebo, these reductions were asymptomatic. LVEF recovered after therapy interruption in all 7 patients treated with this drug.^[Ref]

Gastrointestinal

• Common (1% to 10%): Diarrhea, gastroesophageal reflux disease

Musculoskeletal

• Common (1% to 10%): Back pain, arthralgia

Nervous system

• Very common (10% or more): Dizziness (up to 27%), headache (12.2%)
• Common (1% to 10%): Syncope^[Ref]

Other

• Common (1% to 10%): Fatigue

Respiratory

• Very common (10% or more): Nasopharyngitis (12.2%), dyspnea (14.6%)
• Common (1% to 10%): Upper respiratory tract infection, cough

See also:

Frequently asked questions

• What is the mechanism of action of Camzyos?

Further information

Mavacamten side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer