Names & Terms You Will Hear
Plain-language meanings for the terms your care team may use.
| Term | Meaning |
|---|---|
| Mavacamten | The drug name. It is the medicine inside the pill. |
| Camzyos | The brand name for mavacamten in the United States. |
| Cardiac myosin inhibitor | The medicine class. It calms the tiny muscle 'bridges' that make the heart squeeze too hard. |
| HCM (hypertrophic cardiomyopathy) | A condition where the heart muscle grows too thick and squeezes too hard. |
| Obstructive HCM (oHCM) | The kind of HCM where the thick wall blocks blood from leaving the heart. This is the kind mavacamten treats. |
| LVOT obstruction | Left ventricular outflow tract obstruction. The medical name for that blockage at the heart's exit. |
| Ejection fraction (EF) | The share of blood the heart pumps out with each beat. A normal EF is about 55 to 70 out of 100. |
| Echocardiogram (echo) | A painless heart ultrasound. It measures the squeeze, the blockage, and the pumping strength. |
| REMS | Risk Evaluation and Mitigation Strategy. A required safety program that makes sure echoes are done on schedule. |
Mavacamten treats the obstructive type of HCM. It is for people whose thick heart wall blocks blood from leaving the heart (obstructive HCM). It is not used for non-obstructive HCM, where there is no blockage at the heart's exit.
What Is Mavacamten (Camzyos)?
- Mavacamten (brand Camzyos) is a pill for adults with symptomatic obstructive HCM. It is the first medicine of its kind.
- In HCM, the heart muscle grows too thick and squeezes too hard. The thickened wall can block blood from leaving the heart.
- Mavacamten is a cardiac myosin inhibitor. Myosin is the part of muscle that makes it contract. The pill calms some of that over-squeezing.
- With a softer squeeze, the thick wall blocks less. Blood leaves the heart more easily and symptoms ease.
- It is taken once a day by mouth. Your care team starts low and adjusts the dose using your echo results.
- It treats the obstructive type of HCM. It is not for the non-obstructive type, where there is no blockage at the exit.
How Mavacamten Works
- Heart muscle squeezes when tiny parts called myosin and actin pull on each other, like rows of hands gripping a rope.
- In HCM, too many of these grips are active at once, so the muscle squeezes too hard and stiffens.
- Mavacamten is a cardiac myosin inhibitor. It calms some of those grips so fewer are pulling at the same time.
- With a gentler squeeze, the thick wall does not crowd the heart's exit as much, and blood leaves more freely.
- Because it directly changes the squeeze, its strength is measured with echoes — not with blood pressure alone.
Why It Matters
- Many people with obstructive HCM feel short of breath, tired, or lightheaded because the blockage limits blood flow.
- In the EXPLORER-HCM trial, 37 out of 100 people on mavacamten improved on a combined exercise-and-symptom measure, versus 17 out of 100 on placebo.
- People on mavacamten in that trial walked and exercised better, had less blockage at the heart's exit, and felt better day to day.
- In the VALOR-HCM trial, after 16 weeks only 18 out of 100 people on mavacamten still met the criteria for septal reduction surgery, versus 77 out of 100 on placebo.
- That means many people could ease their symptoms with a pill instead of moving straight to a heart procedure.
- The picture below shows how the pill relieves the blockage that causes those symptoms.
Risk Factors
Knowing your personal risks helps your care team take extra precautions.
| Risk Factor | Why It Increases Risk |
|---|---|
| Already low pumping strength | If your ejection fraction is below 55 out of 100, mavacamten is not started. It can lower the EF further. |
| Pregnancy or trying to conceive | Mavacamten can harm an unborn baby. It must not be used in pregnancy. Use reliable birth control while taking it. |
| Certain other medicines | Some drugs change mavacamten's level in the blood. Strong interacting medicines can make it unsafe to combine. |
| A new heart infection or serious illness | Anything that suddenly weakens the heart's squeeze raises the risk of a low EF. Tell your team about new illness. |
| Trouble getting to echo visits | The medicine is only safe with regular echoes. If you cannot keep the echo schedule, it may not be the right choice. |
Treatment Options
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
- Mavacamten is one capsule by mouth once a day. Take it at about the same time each day, with or without food.
- Before you start, you get an echocardiogram to measure your pumping strength (EF). You do not start if the EF is too low.
- Your care team starts at a low dose. They check an echo and adjust the dose over the first weeks to find the right amount for you.
- Echoes are repeated on a set schedule — early on, before any dose increase, and regularly after that. The timeline below shows when.
- If an echo shows the EF has dropped too low, the medicine is paused. The pumping strength usually recovers, and the team restarts at a lower dose.
- Tell every doctor and pharmacist you take mavacamten. Some common medicines change its level and must be reviewed before you start or stop them.
- Mavacamten treats the blockage in obstructive HCM. It works alongside the rest of your HCM care.
- Learn more in our hypertrophic cardiomyopathy (HCM) guide, our beta-blocker guide, our heart genetic testing guide, our weak heart pump (low EF) guide, and our ARNI (Entresto) guide.
The Echo-Monitoring Program (REMS)
- Mavacamten is given through a required safety program called REMS (Risk Evaluation and Mitigation Strategy).
- Under REMS, your doctor and your pharmacy must be specially certified to prescribe and fill the medicine.
- A current echocardiogram showing a safe pumping strength must be on file before each refill is released.
- If the EF is too low at an echo, the refill is held and the medicine is paused until your strength recovers.
- This program exists for one reason: to make sure the echoes happen on time so a low EF is caught early.
Regular echoes are required — do not skip them. Mavacamten's main risk is lowering your heart's pumping strength (EF). The only way to catch that early is the echocardiogram schedule. A refill cannot be released without a current echo. If you feel perfectly well, you still need every echo on time.
Comfort Measures at Home (No Medication Needed)
These simple steps support healing and ease symptoms. Use them alongside any medication your doctor prescribes.
- Take your pill at the same time every day. A phone alarm or a weekly pill box helps you stay on track.
- Keep every echo and clinic visit. The echoes are what make this medicine safe to keep taking.
- Carry an up-to-date list of all your medicines and supplements. Show it before any new medicine is added.
- Ask before starting any new drug, including over-the-counter ones, because some change mavacamten's level.
- Tell your team right away about new shortness of breath, swelling, or weight gain — these can be signs of a falling EF.
- If you could become pregnant, use reliable birth control and talk with your team about your plans.
Risks, Benefits, and Alternatives
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
Every choice has trade-offs. Use this table to start the shared decision conversation with your care team.
| Option | Risks | Benefits | Alternatives |
|---|---|---|---|
| Start mavacamten (Camzyos) | Can lower the heart's pumping strength (EF). Needs regular echoes. Not safe in pregnancy. Interacts with some drugs. Dizziness, tiredness. | Better symptoms and exercise. Less blockage at the heart's exit. Fewer people needing a heart procedure. | Stay on beta-blockers or other rate-slowing pills. Consider a septal procedure. |
| Stay on older pills only (beta-blocker or verapamil) | May not fully relieve the blockage. Symptoms can persist. | Long track record. Low cost. No special echo program needed. | Add or switch to mavacamten. Consider a septal procedure if symptoms persist. |
| Septal reduction procedure (surgery or alcohol ablation) | A procedure with its own risks. Usually for severe, drug-resistant cases. | Directly removes or shrinks the thick wall that blocks flow. Long experience at expert centers. | Try mavacamten first in many cases. Surgery stays an option if needed. |
| No new treatment (watchful waiting) | Symptoms and blockage may continue or worsen over time. | Avoids medicine side effects and procedure risks. | Revisit mavacamten or a procedure if symptoms grow. |
Common Misconceptions
| Myth | Reality |
|---|---|
| Mavacamten cures HCM. | It does not cure HCM. It calms the over-squeezing and eases the blockage so you feel better. You keep taking it and stay under care. |
| If I feel fine, I can skip my echocardiograms. | No. The echoes are required for safety. They catch a falling pumping strength before it causes harm, even when you feel well. |
| It is just another beta-blocker. | No. It works in a brand-new way — it calms the heart muscle's contraction directly. It is the first cardiac myosin inhibitor. |
| A temporary drop in pumping strength means permanent damage. | Usually not. If an echo shows a low EF, the pill is paused and the strength almost always recovers. The team then restarts at a lower dose. |
| It is safe to take while pregnant if I feel well. | No. Mavacamten can harm an unborn baby and must not be used in pregnancy. Use reliable birth control and tell your team your plans. |
| Any pharmacy can fill it like a normal prescription. | Not quite. It is given through a required safety program (REMS), so prescribers and pharmacies must be certified and your echoes must be on file. |
Possible Complications
Knowing what can go wrong helps you spot problems early. Most complications are uncommon, especially with treatment.
| Where / What | What Can Happen |
|---|---|
| Pumping strength (EF) | The most important risk: the EF can drop too low. This is why regular echoes are required. The drop usually recovers when the pill is paused. |
| Heart failure symptoms | If the EF falls, you may get short of breath, swelling, or fast weight gain. Report these right away. |
| Dizziness and tiredness | Some people feel dizzy or more tired, especially early on. Tell your team if it is bothersome. |
| Drug interactions | Some medicines raise or lower mavacamten's blood level. The wrong combination can make it unsafe; always have new drugs reviewed. |
| Pregnancy | Mavacamten can seriously harm an unborn baby. It must be stopped before or as soon as pregnancy is known. |
| Atrial fibrillation | Some people with HCM develop an irregular heartbeat. Report a new fast or fluttering heartbeat. |
What is checked, when, and why
| What is checked | When | Why it matters |
|---|---|---|
| Pumping strength (EF) on echo | Before start; weeks 4, 8, 12; then every 12 weeks | Catches a falling EF early so the pill can be paused in time. |
| Echo before a dose increase | Before going up a dose | Makes sure the heart can safely handle more medicine. |
| Other medicines you take | Before starting and any time a drug changes | Some drugs raise or lower mavacamten's level and change its safety. |
| Pregnancy status | Before starting and during treatment | Mavacamten can harm an unborn baby and must not be used in pregnancy. |
Points to Know
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
If you remember nothing else, remember these key points.
- Mavacamten (Camzyos) is a first-of-its-kind pill for symptomatic obstructive HCM.
- It calms an over-squeezing heart so the thick wall blocks less and blood leaves more freely.
- In trials it improved symptoms and exercise, and fewer people needed a septal procedure.
- Its main risk is lowering the heart's pumping strength (EF), so regular echoes are required.
- Echoes are needed before you start, in the early weeks, before any dose increase, and every 12 weeks after.
- If the EF drops, the pill is paused; the strength usually recovers and the team restarts at a lower dose.
- Do not use it in pregnancy, and have any new medicine reviewed because some change its level.
- Take it once a day and never skip your echo visits, even when you feel well.
When to Call Us — and When to Call 911
Shown in English for your safety — this section is not automatically translated. Confirm with your doctor or call the office.
If you are not sure, call. We would rather hear from you twice than miss a real problem.
- Call 911 now for fainting, chest pain that will not stop, or trouble breathing that is severe or sudden.
- Call 911 for a very fast or pounding heartbeat with dizziness, or if you nearly pass out.
- Call us if you have new or worse shortness of breath, swelling in your legs or belly, or fast weight gain — these can be signs of a low EF.
- Call us if you feel very dizzy, lightheaded, or unusually tired.
- Call us before starting or stopping any new medicine or supplement, because some change mavacamten's level.
- Call us right away if you are pregnant or think you might be — mavacamten must be stopped.
- Call us if you cannot keep a scheduled echocardiogram so we can plan your refills safely.
Office: (727) 943-5200
Trusted Resources
Independent, evidence-based pages we recommend for deeper reading.
- American Heart Association — Hypertrophic Cardiomyopathy — Patient-friendly overview of HCM and how it is treated.
- Cleveland Clinic — Mavacamten (Camzyos) — Plain-language drug page on how mavacamten works, the echo monitoring, and key cautions.
- MedlinePlus — Mavacamten — NIH/NLM drug page on side effects, the pregnancy warning, and the interaction list.
- Hypertrophic Cardiomyopathy Association (HCMA) — Patient advocacy group with living-with-HCM support and family screening guidance.
Sources Used to Build This Guide
- American Heart Association — Hypertrophic Cardiomyopathy Treatment [patient_education] — Frames mavacamten within obstructive HCM care: how a cardiac myosin inhibitor reduces outflow obstruction and symptoms.
- Cleveland Clinic — Mavacamten (Camzyos) [patient_education] — Plain-language overview of dosing, REMS echo monitoring for reduced EF, and the drug interactions patients must know.
- EXPLORER-HCM Trial — Mavacamten for Obstructive HCM (Lancet 2020) [clinical_trial] — Pivotal trial: 37% of mavacamten patients vs 17% on placebo met the primary exercise-plus-symptom endpoint at week 30; source for efficacy numbers.
- VALOR-HCM Trial — Mavacamten in Patients Referred for Septal Reduction (JAMA Cardiology 2023) [clinical_trial] — At 16 weeks only 18% of mavacamten patients still met criteria for septal reduction surgery vs 77% on placebo; source for the procedure-avoidance numbers.
- 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy [guideline] — Authoritative basis for the place of cardiac myosin inhibitors in obstructive HCM therapy and for the monitoring requirements.
- FDA — CAMZYOS (mavacamten) Prescribing Information & Boxed Warning [fda_label] — Primary source for the boxed warning on heart-failure risk from low ejection fraction, the echocardiogram schedule, and CYP2D6/CYP3A4 interactions.
- FDA — CAMZYOS REMS (Risk Evaluation and Mitigation Strategy) Program [fda_label] — Explains the required safety program: prescriber and pharmacy certification and the echocardiogram schedule before each refill.
- MedlinePlus — Mavacamten [patient_education] — NIH/NLM plain-language drug page on how to take mavacamten, side effects, the pregnancy warning, and the interaction list.
- Bristol Myers Squibb — CAMZYOS Patient Information [patient_education] — Manufacturer patient resource for how the REMS echo program works day to day and what to expect at each visit.
- Hypertrophic Cardiomyopathy Association (HCMA) — Patient Resources [patient_education] — Patient advocacy organization with living-with-HCM guidance, family screening information, and treatment-decision support.
