Pronunciation: Kam-zai-os
Generic name: mavacamten
Dosage form: capsules (2.5mg, 5mg, 10mg, 15mg)
Drug class: Miscellaneous cardiovascular agents

Medically reviewed by Melisa Puckey, BPharm. Last updated on Apr 29, 2025.

What is Camzyos?

Camzyos (mavacamten) is a prescription medicine used to treat symptomatic obstructive hypertrophic cardiomyopathy (HCM), helping improve shortness of breath and the ability to be active.  Camzyos is a cardiac myosin inhibitor that relaxes heart muscles so the heart can fill with more blood and pump blood around your body more effectively.

In obstructive hypertrophic cardiomyopathy (HCM), the walls of the heart become excessively thickened and stiff. This reduces blood flow from the heart to your body, which causes symptoms of shortness of breath, rapid heartbeat, feeling light-headed, chest pain, fainting, and tiredness. Camzyos relaxes the heart muscles and reduces heart obstruction, which improves your ability to be active and other symptoms.

How does Camzyos work?

The heart pumps blood around the body as heart muscles contract and release. Heart muscles contract when two proteins called myosin and actin join together, and then muscles relax when myosin and actin are not joined. In obstructive HCM, too many myosin and actin connect, making the heart contract too much, thickening the heart walls, reducing blood flow from the heart, and causing symptoms.

Camzyos's mechanism of action is a cardiac myosin inhibitor that works by binding to the myosin protein, which stops the actin proteins from binding to it. As a result, the heart muscle relaxes, the heart fills with more blood, and it can pump more effectively. Camzyos is an allosteric and reversible inhibitor selective for cardiac myosin.

Camzyos Indications

Camzyos is indicated for adults with symptomatic obstructive hypertrophic cardiomyopathy (HCM) to help improve functional capacity and symptoms. It can be used in patients with New York Heart Association (NYHA) class II-III obstructive HCM. Camzyos became an FDA-approved medicine on April 28, 2022.

Camzyos side effects

Common Camzyos side effects

Common Camzyos side effects include dizziness (27%) or fainting (6%).

Serious Camzyos side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Camzyos may cause serious side effects. Call your doctor at once if you have:

• heart failure symptoms, such as shortness of breath, chest pain, tiredness, swelling in your legs, rapid weight gain, or racing or pounding heartbeats.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Camzyos REMS program

Camzyos is only available through the Camzyos REMS program, which is required by the FDA to monitor the safe use of this medication. The REMS  (Risk Evaluation and Mitigation Strategy) program is required as this medicine can cause the heart muscles to become too relaxed, which increases the risk of heart failure.  Your doctor will review and discuss the REMS Patient Brochure with you and talk to you about how to enroll in the program.

Warnings

Camzyos may cause serious side effects, and carries a Boxed Warning for a risk of heart failure.

Heart failure:

Heart failure is a condition where the heart cannot pump with enough force. Heart failure is a serious condition that can lead to death. You must have echocardiograms before you take the first dose and also during your treatment with this medicine. This is important to help your healthcare provider understand how your heart is responding to this medicine. People who develop a serious infection or irregular heartbeat have a greater risk of heart failure during treatment.

Call your doctor at once if you have shortness of breath, chest pain, tiredness, swelling in your legs, rapid weight gain, or racing or pounding heartbeats.

The risk of heart failure is also increased when Camzyos is taken with certain other medicines. Tell your healthcare provider about the medicines you take, both prescribed and obtained over-the-counter, before and during treatment.

Because of the serious risk of heart failure, this medicine is only available through a restricted program called the Camzyos Risk Evaluation and Mitigation Strategy (REMS) Program.

See Camzyos side effects for information about side effects.

It is not known if Camzyos is safe and effective in children.

Before taking this medicine

Your treatment plan may change if you also use certain other medications such as:

• nefazodone;
• St. John's wort;
• an antibiotic eg.clarithromycin, rifabutin, rifampin, rifapentine, telithromycin;
• antifungal medicine eg. itraconazole, ketoconazole;
• antiviral medicine for HIV or hepatitis C eg. boceprevir, cobicistat, dasabuvir, elvitegravir, indinavir, lopinavir/ritonavir, nelfinavir, ombitasvir, paritaprevir saquinavir, telaprevir, tipranavir;
• cancer medicine eg. apalutamide, enzalutamide, mitotane;
• seizure medicine eg. carbamazepine, oxcarbazepine, phenytoin, primidone;
• steroid medicine eg. dexamethasone, prednisone;

Tell your doctor if you have ever had:

• an irregular heartbeat;
• heart failure; or
• if you have an infection.

Pregnancy

Camzyos may harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant before using this medicine. Use effective birth control while using this medicine and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Hormonal contraceptives containing a combination of ethinyl estradiol and norethindrone may be used with this medicine, but it can make other birth control pills less effective. Ask your doctor about all birth control options, such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge.

Breastfeeding

Ask a doctor if it is safe to breastfeed while using this medicine.

How should I take Camzyos?

Take Camzyos once a day.

Swallow the capsule whole. Do not break, open, or chew the capsule.

You will start with an initial dose, and over weeks, your Doctor will increase your dose depending on how you respond to the medicine.

Your healthcare provider may change your dose, temporarily stop, or permanently stop your treatment if you have certain side effects.

Take Camzyos capsules exactly as your healthcare provider tells you to take them.

Do not change your dose without talking to your healthcare provider first.

What happens if I miss a dose?

If you miss a dose, take it as soon as possible and take your next dose at your regularly scheduled time the next day. Do not take 2 doses on the same day to make up for a missed dose.

What happens if I overdose?

If you take too much or overdose, call your healthcare provider or go to the nearest hospital emergency room right away.

Dosing information

Usual Adult Dosage for Hypertrophic Cardiomyopathy

Starting dose: 5 mg orally once a day

• Reduce starting dosage to 2.5 mg/day in those taking moderate CYP2C19 inhibitors or a strong CYP3A4 inhibitor.
• See the Camzyos Prescribing Information for complete dosing information and instructions for regular left ventricular ejection fraction (LVEF) and Valsalva left ventricular outflow tract (LVOT) gradient assessment.

Allowable subsequent doses with titration: 2.5, 5, 10, or 15 mg orally once a day.

Available Strengths 

• 2.5mg, 5mg, 10mg, 15mg capsules.

What other drugs will affect Camzyos?

Tell your doctor about all your other medicines, especially:

• moderate to strong CYP2C19 inhibitors or strong CYP3A4 inhibitors
• moderate to strong CYP2C19 inducers or moderate to strong CYP3A4 inducers
• heart medications such as disopyramide, ranolazine, or verapamil that are taken with a beta blocker, or diltiazem with a beta blocker, as these medications and combinations increase the risk of left ventricular systolic dysfunction and heart failure symptoms
• other medicines to treat obstructive hypertrophic cardiomyopathy; or
• omeprazole, esomeprazole, or cimetidine.

Camzyos is an inducer of CYP3A4, CYP2C9, and CYP2C19. Concomitant use with CYP3A4, CYP2C9, or CYP2C19 substrates may reduce the plasma concentration of these drugs. Ask your healthcare provider if you are taking one of these medications. 

Progestin and ethinyl estradiol are CYP3A4 substrates. Concomitant use of Camzyos may decrease blood levels of certain progestins, which may lead to contraceptive failure. Combined hormonal contraceptives (CHCs) containing a combination of ethinyl estradiol and norethindrone may be used, but if other CHCs are used, patients should add nonhormonal contraception (such as condoms) during concomitant use and for 4 months after the last dose of Camzyos.

This list is not complete. Other drugs may affect Camzyos, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Click on the link below to check for interactions with Camzyos.

Camzyos Prescribing Information

Review the Camzyos Package Insert for more detailed information about this medicine. Discuss any medical questions you have with your doctor or other health care provider. This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

Storage

Store at room temperature between 68°F to 77°F (20°C to 25°C).

Ingredients

Active ingredient: mavacamten

Inactive ingredients: croscarmellose sodium, hypromellose, magnesium stearate (non-bovine), mannitol, and silicon dioxide. The capsule contains black iron oxide, gelatin, red iron oxide, titanium dioxide, and yellow iron oxide.

Company

Bristol-Myers Squibb Company, Princeton, NJ 08543 USA

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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