Home Drug Guide Mavacamten

Drug Guide

Generic Name

Mavacamten

Brand Names Camzyos

Classification

Therapeutic: Cardiovascular agent

Pharmacological: Myosin inhibitor

FDA Approved Indications

Treatment of symptomatic New York Heart Association (NYHA) class II-III obstructive hypertrophic cardiomyopathy (HCM) to improve functional capacity and symptoms

Mechanism of Action

Mavacamten is a selective allosteric inhibitor of cardiac myosin. It reduces excessive myosin-actin cross-bridge formation, decreasing hypercontractility of the myocardium, thereby alleviating left ventricular outflow tract obstruction and related symptoms in HCM.

Dosage and Administration

Adult: Initial dose of 5 mg orally once daily. Dose adjustments are based on clinical response and left ventricular ejection fraction (LVEF). The maximum dose is 15 mg daily.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution; monitor closely due to potential for increased sensitivity.

Renal Impairment: No specific adjustment recommended; however, renal function should be monitored.

Hepatic Impairment: Use with caution; initiate at lower doses due to hepatic metabolism.

Pharmacokinetics

Absorption: Rapidly absorbed after oral administration; food does not significantly affect absorption.

Distribution: Highly plasma protein-bound (~97%), primarily to albumin.

Metabolism: Primarily metabolized by hepatic CYP2C19 and CYP3A4 enzymes.

Excretion: Metabolites eliminated mainly via feces; minimal renal excretion.

Half Life: Approximately 46 hours, allowing once-daily dosing.

Contraindications

Severe hepatic impairment
Known hypersensitivity to mavacamten

Precautions

Monitor LVEF regularly; avoid in patients with baseline LVEF <50%
Use with caution in patients with impaired hepatic function
Potential for hypotension and heart failure exacerbation

Adverse Reactions - Common

Headache (Common)
Decreased LVEF (Common)
Fatigue (Common)

Adverse Reactions - Serious

Heart failure (Uncommon)
Arrhythmias (Uncommon)
Hypotension (Uncommon)

Drug-Drug Interactions

CYP2C19 inhibitors (e.g., omeprazole, fluoxetine) may increase mavacamten levels
CYP3A4 inhibitors (e.g., ketoconazole) may increase levels
CYP2C19 inducers may decrease efficacy

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor LVEF before and during treatment. Assess for symptoms of heart failure. Check hepatic function periodically.

Diagnoses:

Risk for decreased cardiac output
Risk for injury related to hypotension

Implementation: Administer as prescribed, monitor cardiac function, and counsel on recognizing adverse effects.

Evaluation: Evaluate improvement in symptoms and maintain LVEF within safe limits.

Patient/Family Teaching

Take mavacamten exactly as prescribed.
Report symptoms such as dizziness, fainting, shortness of breath, or swelling.
Attend regular follow-up appointments for monitoring of cardiac function.
Inform healthcare providers of all medications being taken.

Special Considerations

Black Box Warnings:

Reduced LVEF: Mavacamten can cause reduction in LVEF; monitor closely.

Genetic Factors: CYP2C19 genotype may affect drug metabolism; poor metabolizers may have increased exposure.

Lab Test Interference: May affect assessment of cardiac function; interpret with caution.

Overdose Management

Signs/Symptoms: Severe hypotension, bradycardia, symptoms of heart failure.

Treatment: Discontinue drug; provide supportive care, monitor cardiac status, and manage symptoms accordingly.

Storage and Handling

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

Stability: Stable up to the expiration date when stored properly.