What is Mavacamten: Uses, Dosage, Side Effects and More

Mavacamten is a prescription medication specifically designed to treat hypertrophic cardiomyopathy, a condition where your heart muscle becomes abnormally thick. This targeted therapy works by helping your heart pump more efficiently when the muscle walls have grown too thick to function properly.

If you or someone you love has been diagnosed with hypertrophic cardiomyopathy, you might feel overwhelmed by the complexity of this condition. Mavacamten represents a significant breakthrough in treatment, offering hope for people who previously had limited options beyond surgery.

What is Mavacamten?

Mavacamten is a first-in-class cardiac myosin inhibitor that directly targets the root cause of hypertrophic cardiomyopathy. It works by binding to the thick filaments in your heart muscle, reducing the excessive force that causes your heart to work too hard.

Think of your heart muscle as an overenthusiastic worker that's trying too hard. Mavacamten essentially tells those muscle fibers to calm down and work more efficiently. This medication was specifically developed after decades of research into the genetic and molecular causes of hypertrophic cardiomyopathy.

The drug is marketed under the brand name Camzyos and represents a major advancement in treating this inherited heart condition. Unlike older treatments that only managed symptoms, mavacamten actually addresses the underlying problem at the cellular level.

What is Mavacamten Used For?

Mavacamten is prescribed for adults with obstructive hypertrophic cardiomyopathy who continue to have symptoms despite taking other heart medications. Your doctor will typically consider this treatment when you experience shortness of breath, chest pain, or fatigue that interferes with your daily activities.

The medication is specifically indicated for symptomatic hypertrophic cardiomyopathy with left ventricular outflow tract obstruction. This means your thickened heart muscle is actually blocking blood flow out of your heart's main pumping chamber, creating a bottleneck that makes your heart work harder.

Your cardiologist might recommend mavacamten if you've tried beta-blockers, calcium channel blockers, or other standard treatments without adequate symptom relief. It's particularly valuable for people who want to avoid or delay surgical interventions like septal myectomy or alcohol septal ablation.

The drug can also be considered for people who aren't good candidates for surgery due to other health conditions or personal preferences. Some patients find that mavacamten helps them return to activities they previously couldn't enjoy due to their symptoms.

How Does Mavacamten Work?

Mavacamten works by directly inhibiting cardiac myosin, the protein responsible for your heart muscle's contraction. In hypertrophic cardiomyopathy, these muscle fibers contract too forcefully, creating the obstruction and symptoms you experience.

The medication binds to the myosin heads in your heart muscle, preventing them from forming too many cross-bridges with actin filaments. This reduces the hypercontractility that's characteristic of hypertrophic cardiomyopathy, allowing your heart to pump more efficiently with less effort.

This is considered a moderately strong medication that requires careful monitoring. Your doctor will need to track your heart function closely because reducing contractility too much could potentially weaken your heart's pumping ability.

The drug's effects are dose-dependent, meaning higher doses provide more inhibition of muscle contraction. This is why your doctor will start with a lower dose and gradually adjust it based on how your heart responds and how your symptoms improve.

How Should I Take Mavacamten?

Take mavacamten exactly as your doctor prescribes, typically once daily with or without food. You can take it with water, milk, or juice, and there are no specific dietary restrictions that affect how the medication works.

You don't need to take mavacamten with food, but taking it at the same time each day helps maintain consistent levels in your system. Many people find it easier to remember if they take it with breakfast or dinner as part of their routine.

Swallow the capsule whole without crushing, chewing, or opening it. The medication is formulated to release properly when swallowed intact, and altering the capsule could affect how your body absorbs it.

If you miss a dose, take it as soon as you remember, unless it's almost time for your next scheduled dose. In that case, skip the missed dose and continue with your regular schedule. Never double up on doses to make up for a missed one.

How Long Should I Take Mavacamten For?

Mavacamten is typically a long-term treatment that you may need to take indefinitely to maintain symptom relief. Your doctor will monitor your response and may adjust your dose over time, but stopping the medication usually means your symptoms will return.

Most people start seeing improvement in their symptoms within 4 to 12 weeks of starting treatment. However, the full benefits may take several months to become apparent as your heart adjusts to the medication's effects.

Your doctor will schedule regular follow-up appointments to monitor your heart function through echocardiograms and other tests. These visits help ensure the medication is working effectively without causing your heart function to become too weak.

Some people may need to stop mavacamten temporarily if their heart function decreases too much, but this is usually reversible. Your doctor will carefully balance the benefits of symptom relief against any potential risks to your heart's pumping ability.

What Are the Side Effects of Mavacamten?

Like all medications, mavacamten can cause side effects, though not everyone experiences them. The most important thing to understand is that your doctor will monitor you closely to catch any concerning effects early.

Here are the most common side effects you might experience:

• Dizziness or lightheadedness, especially when standing up quickly
• Fatigue or feeling more tired than usual
• Shortness of breath, particularly during physical activity
• Chest pain or discomfort
• Swelling in your legs, ankles, or feet
• Irregular heartbeat or palpitations

These symptoms often improve as your body adjusts to the medication, but you should always report them to your doctor.

Now, let's discuss the more serious but less common side effects that require immediate medical attention:

• Severe shortness of breath that worsens or occurs at rest
• Significant swelling that doesn't improve with elevation
• Chest pain that's severe or different from your usual symptoms
• Fainting or near-fainting episodes
• Rapid or irregular heartbeat that concerns you

The most serious potential side effect is a significant reduction in your heart's pumping function, which is why regular monitoring is so important. Your doctor will use echocardiograms to watch for this and will adjust your dose or stop the medication if needed.

Some rare but serious side effects include severe allergic reactions, liver problems, or dangerous drops in blood pressure. While these are uncommon, it's important to be aware of them and seek immediate medical care if you experience signs like severe rash, yellowing of skin or eyes, or persistent nausea and vomiting.

Who Should Not Take Mavacamten?

Mavacamten isn't suitable for everyone with hypertrophic cardiomyopathy. Your doctor will carefully evaluate whether this medication is safe for your specific situation.

You should not take mavacamten if you have certain heart conditions that could be worsened by reducing your heart's contractility:

• Severe heart failure or significantly reduced heart function
• Certain types of arrhythmias that require strong heart contractions
• Severe kidney disease that affects medication clearance
• Liver disease that impairs your body's ability to process the drug
• Known allergy to mavacamten or any of its ingredients

Your doctor will also be cautious about prescribing mavacamten if you have other conditions that affect your heart.

Special considerations apply for certain groups of people:

• Pregnant women should not take mavacamten, as it may harm the developing baby
• Women of childbearing age need reliable contraception while taking this medication
• Breastfeeding mothers should discuss alternatives with their doctor
• Older adults may need dose adjustments due to age-related changes in kidney or liver function
• People taking certain other medications may have drug interactions

Your doctor will review your complete medical history and current medications before prescribing mavacamten to ensure it's safe for you.

Mavacamten Brand Name

Mavacamten is sold under the brand name Camzyos, manufactured by Bristol Myers Squibb. This is currently the only brand name available for this medication in the United States.

Camzyos comes in capsule form in different strengths: 2.5 mg, 5 mg, 10 mg, and 15 mg. Your doctor will determine the right starting dose based on your specific condition and response to treatment.

Since mavacamten is a newer medication, generic versions are not yet available. The brand name Camzyos is what you'll see on your prescription bottle and what your pharmacist will dispense.

Mavacamten Alternatives

If mavacamten isn't suitable for you or doesn't provide adequate symptom relief, several alternative treatments are available. Your doctor will work with you to find the best approach for your specific situation.

Traditional medication alternatives include:

• Beta-blockers like metoprolol or propranolol, which slow your heart rate and reduce the force of contractions
• Calcium channel blockers such as verapamil, which help your heart muscle relax
• Disopyramide, an antiarrhythmic drug that can reduce obstruction in some people
• Diuretics to help manage fluid retention if you develop heart failure symptoms

These medications have been used for decades and may still be effective for many people with hypertrophic cardiomyopathy.

For people who don't respond well to medications, surgical options remain available:

• Septal myectomy, where a surgeon removes part of the thickened heart muscle
• Alcohol septal ablation, a less invasive procedure that destroys part of the thickened muscle using alcohol
• Implantable cardioverter defibrillator (ICD) for people at high risk of dangerous arrhythmias

Your cardiologist will help you weigh the benefits and risks of each option based on your age, overall health, and personal preferences.

Is Mavacamten Better Than Metoprolol?

Mavacamten and metoprolol work differently and serve different roles in treating hypertrophic cardiomyopathy. Mavacamten directly targets the underlying muscle problem, while metoprolol is a beta-blocker that reduces heart rate and contractility more generally.

Mavacamten may be more effective for people with significant obstruction who haven't responded well to beta-blockers like metoprolol. Clinical studies show that mavacamten can improve exercise capacity and quality of life more than traditional medications in many patients.

However, metoprolol has a longer track record of safety and is much less expensive than mavacamten. Many doctors still prefer to start with metoprolol or similar medications before considering mavacamten, especially for people with mild symptoms.

The choice between these medications depends on your specific symptoms, how well you've responded to other treatments, and your individual risk factors. Some people may actually take both medications together under careful medical supervision.