Mavacamten Dosage

Medically reviewed by Drugs.com. Last updated on Jun 3, 2025.

Usual Adult Dose for Hypertrophic Cardiomyopathy

Starting dose: 5 mg orally once a day
Allowable subsequent doses with titration: 2.5, 5, 10, or 15 mg orally once a day
Maximum dose: 15 mg orally/day

Comments:

• Initiation or up-titration in patients with left ventricular ejection fraction (LVEF) less than 55% is not recommended.
• Patients may develop heart failure during therapy; regular LVEF and Valsalva left ventricular outflow tract (LVOT) gradient assessments are needed for dosing and careful titration to achieve appropriate target Valsalva LVOT gradient while maintaining LVEF at least 50% and avoiding heart failure symptoms.
• The algorithms for treatment INITIATION and MAINTENANCE should be followed for appropriate dosing and monitoring schedules.
• If LVEF is less than 50% during therapy, interrupt treatment as per the dosing algorithm for INTERRUPTION.

Use: For the treatment of patients with symptomatic New York Heart Association (NYHA) class II to III obstructive hypertrophic cardiomyopathy (HCM) to improve functional capacity and symptoms

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Mild to moderate liver dysfunction (Child-Pugh A or B): No adjustment recommended.
Severe liver dysfunction (Child-Pugh C): Data not available

Dose Adjustments

Review the schematic dosing algorithms in the manufacturer product information prior to starting therapy.

INITIATION PHASE:

• Initiate therapy at 5 mg orally once a day (only if LVEF at least 55%)
• During weeks 4, 8, and 12: Therapy should be interrupted for LVEF less than 50% at any clinic visit; therapy should be restarted after 4 weeks of LVEF at least 50%. Follow algorithm for treatment INTERRUPTION.
• For patients on stable therapy with CYP450 2C19 or 3A4 inhibitors, follow manufacturer's dosing instructions.

Week 4:

• If Valsalva LVOT gradient less than 20 mmHg: Reduce dose to 2.5 mg orally once a day.
• If Valsalva LVOT gradient at least 20 mmHg: Maintain dose at 5 mg orally once a day.

Week 8:

• If current dose is 2.5 mg orally once a day AND:
• Valsalva LVOT gradient less than 20 mmHg: Withhold therapy; patient should return to clinic at Week 12.
• Valsalva LVOT gradient at least 20 mmHg: Maintain 2.5 mg orally once a day
• If current dose is 5 mg orally once a day AND:
• Valsalva LVOT gradient less than 20 mmHg: Reduce dose to 2.5 mg orally once a day
• Valsalva LVOT gradient at least 20 mmHg: Patient should be maintained at 5 mg orally once a day.

Week 12:

• If therapy was withheld for Valsalva LVOT gradient less than 20 mmHg: Restart daily dosing at 2.5 mg if LVEF is at least 50%; recheck clinical status and echocardiogram (ECHO) in 4 weeks.
• Maintain the same dose for the next 8 weeks consistent with MAINTENANCE dosing algorithm (unless LVEF is less than 50%)
• If current dose is 2.5 or 5 mg orally once a day: Follow the algorithm for MAINTENANCE phase.

MAINTENANCE PHASE (WEEK 12 AND SUBSEQUENT CLINIC VISITS):

• If LVEF is less than 50%: Interrupt therapy.
• If LVEF is 50 to 55%: Maintain the same dose and follow-up in 3 months.
• If LVEF is at least 55% and Valsalva LVOT gradient less than 30 mmHg: Maintain the same dose. During first 6 month cycle, assess clinical status after 3 months and recheck status and ECHO at 6 months; then monitor every 6 months.
• If LVEF is at least 55% and Valsalva LVOT gradient at least 30 mmHg: Up-titrate to the next higher daily dosing level/tablet strength. Recheck clinical status and ECHO in 4 weeks and maintain the same dose for the next 8 weeks unless LVEF is less than 50%. Further up-titration is allowed after 12 weeks at the same dose level.
• In patients with normal/near-normal Valsalva LVOT gradient (about 30 mmHg) prior to therapy, if LVEF at least 55% and post-exercise LVOT is at least 30 mmHg, increase dose to the next higher dosing level/tablet strength if symptoms persist.

INTERRUPTION OF TREATMENT AT ANY CLINIC VISIT FOR LVEF LESS THAN 50%:

• If LVEF is less than 50%: Interrupt therapy; recheck ECHO every 4 weeks until LVEF at least 50%.
• May resume therapy once LVEF is at least 50%; restart at the next lower dosing level/tablet strength (or restart at 2.5 mg if interrupted at the lowest dose).
• Four weeks after resuming therapy, recheck clinical status and ECHO; maintain the same dose for the next 8 weeks unless LVEF is less than 50%. Follow the algorithm for MAINTENANCE phase.
• For patients on 2.5 mg/day with reoccurrence of LVEF less than 50%: Permanently discontinue therapy.

Dose increases should be delayed when there is intercurrent illness (e.g., serious infection) or arrhythmia (e.g., atrial fibrillation, other uncontrolled tachyarrhythmia) that may impair systolic function; interruption of this drug should be considered in patients with intercurrent illness.

COADMINISTRATION WITH CYP450 2C19 OR 3A4 INHIBITORS:
Patients on STABLE Therapy with a Weak CYP450 2C19 Inhibitor OR Moderate CYP450 3A4 Inhibitor:

• Initiate this drug at 5 mg orally once a day.

Patients on STABLE Therapy with a Moderate CYP450 2C19 Inhibitor OR Strong CYP450 3A4 Inhibitor:

• Initiate this drug at 2.5 mg orally once a day.
• Interrupt treatment if Valsalva LVOT gradient less than 20 mmHg at week 4 or 8.
• May resume therapy after 4 weeks at 2.5 mg orally once a day if LVEF is 50% or greater; if resumed at week 12, recheck clinical status, Valsalva LVOT gradient, and LVEF in 4 weeks, and maintain current dose for next 8 weeks unless LVEF less than 50%.

Patients Starting NEW Therapy with a Weak to Moderate CYP450 2C19 Inhibitor OR Moderate to Strong CYP450 3A4 Inhibitor:

• For short-term use (1 week): Interrupt therapy for the duration of treatment with an inhibitor.
• For longer-term use (greater than 1 week): Reduce dose to the next lower dosing level/tablet strength.
• Schedule clinical and echocardiographic assessment 4 weeks after inhibitor initiation.
• This drug should not be up-titrated until 12 weeks after inhibitor initiation.
• Avoid initiation of inhibitors in patients on stable treatment with 2.5 mg/day as a lower daily dose is not available.

Precautions

The US FDA requires a Risk Evaluation and Mitigation Strategy (REMS) for mavacamten. It includes elements to assure safe use and an implementation system. For additional information: www.accessdata.fda.gov/scripts/cder/rems/index.cfm

US BOXED WARNING: RISK OF HEART FAILURE:

• This drug reduces LVEF and can cause heart failure due to systolic dysfunction.
• Echocardiogram assessments of LVEF are required before and during therapy. Treatment initiation in patients with LVEF less than 55% is not recommended; therapy should be interrupted if LVEF is less than 50% at any visit or if the patient has heart failure symptoms or worsening clinical status.
• Coadministration with certain CYP450 inhibitors or stopping certain CYP450 inducers may increase the risk of heart failure due to systolic dysfunction; therefore, the use of this drug is contraindicated with:
• Strong CYP450 2C19 inhibitors
• Moderate to strong CYP450 2C19 or 3A4 inducers
• Because of the risk of heart failure due to systolic dysfunction, this drug is available only through a restricted program under a REMS called Camzyos REMS Program.

CONTRAINDICATIONS:

• Coadministration with strong CYP450 2C19 inhibitors
• Coadministration with moderate to strong CYP450 2C19 or 3A4 inducers

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Before therapy, confirm absence of pregnancy and the usage of effective contraception in patients of childbearing potential.
• Prior to treatment, consider assessing post-exercise LVOT gradient in symptomatic patients with normal or near normal gradients.
• Do not initiate or up-titrate this drug in patients with LVEF less than 55%.
• Administer without regard to food.
• Swallow capsules whole; do not break, open, or chew the capsules.

Storage requirements:

• Store at 20C to 25C (68F to 77F); excursions permitted to 15C to 30C (59F to 86F).

General:

• Daily dosing takes weeks to reach steady-state drug levels and therapeutic effects; genetic variation in metabolism and drug interactions can cause large differences in exposure.

REMS Program: In the US, this drug is only available through a restricted program called the CAMZYOS REMS Program due to the risk of heart failure due to systolic dysfunction. Notable requirements of the program include:

• Prescribers must be certified by enrolling in the program.
• Patients must enroll in the program and comply with ongoing monitoring requirements.
• Pharmacies must be certified by enrolling in the program and must only dispense to patients that are authorized to receive this drug.
• Wholesalers and distributors must only distribute to certified pharmacies.
• Further information is available at www.CAMZYOSREMS.com or by phone at 1-833-628-7367.

Monitoring:

• Cardiovascular: LVEF, Valsalva LVOT, ECHO (before and regularly during therapy)
• General: Clinical status (before and regularly during therapy)

Patient advice:

• Read the US FDA-approved patient labeling (Medication Guide).
• Heart Failure: Instruct patients that they should undergo regular cardiac function monitoring using echocardiography to watch for any signs of heart failure. Patients should promptly report any indications or symptoms of heart failure to their healthcare provider.
• Drug Interactions: Patients should be advised to inform their healthcare providers about all concomitant medications they are using, including over-the-counter medications (such as omeprazole, esomeprazole, or cimetidine) and supplements, both before and during their treatment.
• This drug is accessible through a controlled program (CAMZYOS REMS Program), and patients need to be informed of the program requirements, enrolled in the program and adhere to ongoing monitoring requirements. Additionally, this drug can only be prescribed by certified healthcare providers and can be obtained solely from certified pharmacies participating in the program. Patients should be provided with the contact information and website details for obtaining the product.

Embryo-Fetal Toxicity:

• Pregnant females and patients of reproductive age should be cautioned about the potential risk to a developing fetus. Patients of reproductive age should also be advised to promptly inform their healthcare provider of any known or suspected pregnancies.
• Patients of reproductive age should use effective contraception while undergoing this treatment and continue this contraception for 4 months following the last dose. For patients using CHCs (combination hormonal contraceptives), it is recommended to consider an alternative contraceptive method or incorporate nonhormonal contraception, as this drug may reduce the efficacy of CHCs.
• Patients exposed to this drug during pregnancy should be informed about a pregnancy safety study that monitors pregnancy outcomes. These patients should be encouraged to report their pregnancies to Bristol-Myers Squibb at 1-800-721-5072 or via WWW.BMS.COM.

Instructions for taking this drug:

• Patients should be instructed to swallow capsules whole.
• If a patient misses a dose of this drug, they should take the missed dose as soon as possible on the same day, and the next scheduled dose should be taken at the usual time on the following day. Patients should avoid taking two doses on the same day.

Frequently asked questions

• What is the mechanism of action of Camzyos?

See also:

Further information

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

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