mavacamten (Rx)

Obstructive Hypertrophic Cardiomyopathy

Indicated for symptomatic New York Heart Association class II-III obstructive hypertrophic cardiomyopathy (HCM) to improve exercise capacity and symptoms

Starting dose: 5 mg PO qDay

Allowable subsequent doses with titration are 2.5, 5, 10, or 15 mg qDay

Initiation or up-titration in patients with left ventricular ejection fraction (LVEF) <55% not recommended

Patients may develop heart failure (HF) while taking mavacamten; regular LVEF and Valsalva left ventricular outflow tract (LVOT) gradient assessment required for careful titration to achieve an appropriate target Valsalva LVOT gradient, while maintaining LVEF ≥50% and avoiding HF symptoms

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

When initiating or titrating, first consider LVEF then consider the Valsalva LVOT gradient and patient clinical status to guide appropriate dosing (see algorithm in prescribing information)

Initiation phase dosing (week 4)

• Valsalva LVOT gradient <20 mmHg: Reduce dose to 2.5 mg/day
• Valsalva LVOT gradient ≥20 mmHg: Maintain at 5 mg/day

Initiation phase dosing (week 8)

• Taking 2.5 mg/day

  • Valsalva LVOT gradient <20 mmHg: Withhold drug and resume at Week 12
  • Valsalva LVOT gradient ≥20 mmHg: Maintain at 2.5 mg/day

• Taking 5 mg/day

  • Valsalva LVOT gradient <20 mmHg: Reduce dose to 2.5 mg/day
  • Valsalva LVOT gradient ≥20 mmHg: Maintain at 5 mg/day

Initiation phase dosing (week 12)

• Taking 2.5 mg/day

  • Valsalva LVOT gradient <20 mmHg: Restart on 2.5 mg if LVEF ≥50% and recheck clinical status and echocardiogram (ECHO) in 4 weeks
  • Maintain same dose for next 8 weeks, unless LVEF <50%

• Taking 5 mg/day

  • Refer to maintenance dosing algorithm

Maintenance phase dosing (week 12 and q12wk)

• LVEF <50%: Interrupt treatment

• Maintain on same dose and follow-up 12 weeks later

  • LVEF 50-55%, regardless of Valsalva LVOT gradient OR,
  • LVEF ≥55% and Valsalva LVOT gradient <30 mmHg

• LVEF ≥55% and Valsalva LVOT gradient ≥30 mmHg

  • Up-titration to next higher daily dose level (eg, 2.5 mg to 5 mg; 5 mg to 10 mg; 10 mg to 15 mg)
  • Recheck clinical status and ECHO in 4 weeks and maintain same dose for next 8 weeks unless LVEF <50%
  • Further up-titration allowed after 12 weeks of treatment on same dose level

Treatment interruption if LVEF <50%

• LVEF <50%

  • Interrupt treatment
  • Recheck ECHO parameters q4wk until LVEF ≥50%
  • Permanently discontinue if LVEF <50% twice on 2.5 mg/day

• LVEF ≥50%

  • Restart at next lower daily dose; if interrupted at 2.5 mg, restart at 2.5 mg
  • Recheck clinical status and ECHO in 4 weeks and maintain the same dose for the next 8 weeks unless LVEF <50%, THEN
  • Follow maintenance phase dosage
  • Delay dose increases when there is intercurrent illness (eg, serious infection) or arrhythmia (eg, atrial fibrillation, other uncontrolled tachyarrhythmia) that may impair systolic function
  • Consider interruption in patients with intercurrent illness

Dosage Modifications

Coadministration with weak CYP2C19 or moderate CP3A4 inhibitors

• On stable therapy with weak CYP2C19 inhibitor or a moderate CYP3A4 inhibitor: Initiate at recommended starting dose (5 mg/day)

• Initiating weak CYP2C19 inhibitor or moderate CYP3A4 inhibitor

  • Reduce mavacamten dose by 1 dosage level
  • Schedule clinical and ECHO assessment 4 weeks after inhibitor initiation, and do not up-titrate mavacamten until 12 weeks after inhibitor initiation
  • Avoid initiation of concomitant weak CYP2C19 and moderate CYP3A4 inhibitors in patients who are on stable treatment with mavacamten 2.5 mg/day (lower dose unavailable)

Renal impairment

• Mild-to-moderate (eGFR 30-89 mL/min/1.73 m²): No dosage adjustment required
• Severe impairment and kidney failure, including patients on dialysis (eGFR <30 mL/min/1.73 m²): Unknown

Hepatic impairment

• Mild-to-moderate (Child-Pugh A or B): No dosage adjustment required; although AUC increases, no additional dose adjustment required owing to recommended dose titration algorithm and monitoring
• Severe (Child-Pugh C): Unknown

Dosing Considerations

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

Confirm absence of pregnancy and usage of effective contraception in females of reproductive potential before initiating

Safety and efficacy not established

Contraindicated (89)

• abiraterone

  abiraterone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• amobarbital

  amobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• apalutamide

  apalutamide will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  apalutamide will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• armodafinil

  armodafinil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  armodafinil will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• atazanavir

  atazanavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• belzutifan

  belzutifan will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• bexarotene

  bexarotene will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• bortezomib

  bortezomib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• bosentan

  bosentan will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• butabarbital

  butabarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• butalbital

  butalbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• cannabidiol

  cannabidiol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• carbamazepine

  carbamazepine will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  carbamazepine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• cenobamate

  cenobamate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  cenobamate will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• chloramphenicol

  chloramphenicol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  chloramphenicol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• clarithromycin

  clarithromycin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• cobicistat

  cobicistat will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• conivaptan

  conivaptan will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• dabrafenib

  dabrafenib will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  dabrafenib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• darunavir

  darunavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• delavirdine

  delavirdine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• dexlansoprazole

  dexlansoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• efavirenz

  efavirenz will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  efavirenz will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• elagolix

  elagolix will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• encorafenib

  encorafenib decreases levels of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• enzalutamide

  enzalutamide will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  enzalutamide will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• eslicarbazepine acetate

  eslicarbazepine acetate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  eslicarbazepine acetate will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• esomeprazole

  esomeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• etravirine

  etravirine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  etravirine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• fedratinib

  fedratinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fexinidazole

  fexinidazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fluconazole

  fluconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fluoxetine

  fluoxetine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fluvoxamine

  fluvoxamine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fosphenytoin

  fosphenytoin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  fosphenytoin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• gemfibrozil

  gemfibrozil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• grapefruit

  grapefruit will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• idelalisib

  idelalisib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• indinavir

  indinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• isoniazid

  isoniazid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• itraconazole

  itraconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• ivosidenib

  ivosidenib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ketoconazole

  ketoconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  ketoconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lansoprazole

  lansoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• levoketoconazole

  levoketoconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lonafarnib

  lonafarnib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  lonafarnib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lopinavir

  lopinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  lopinavir will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.

• loratadine

  loratadine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lorlatinib

  lorlatinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• mifepristone

  mifepristone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• mitapivat

  mitapivat will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  mitapivat will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• mitotane

  mitotane will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• mobocertinib

  mobocertinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• modafinil

  modafinil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  modafinil will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nafcillin

  nafcillin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nefazodone

  nefazodone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• nelfinavir

  nelfinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• nicardipine

  nicardipine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• nirmatrelvir/ritonavir

  nirmatrelvir/ritonavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• omeprazole

  omeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• pantoprazole

  pantoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• pentobarbital

  pentobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• pexidartinib

  pexidartinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• phenobarbital

  phenobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• phenytoin

  phenytoin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  phenytoin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• posaconazole

  posaconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• primidone

  primidone will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• propofol

  propofol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• rabeprazole

  rabeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• rifabutin

  rifabutin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• rifampin

  rifampin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  rifampin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• rifapentine

  rifapentine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ritonavir

  ritonavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• rucaparib

  rucaparib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  rucaparib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• saquinavir

  saquinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• secobarbital

  secobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• sertraline

  sertraline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• sitaxentan

  sitaxentan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• sotorasib

  sotorasib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• St John's Wort

  St John's Wort will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• stiripentol

  stiripentol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  stiripentol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• telotristat ethyl

  telotristat ethyl will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ticlopidine

  ticlopidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• tipranavir

  tipranavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• tranylcypromine

  tranylcypromine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• triclabendazole

  triclabendazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• voriconazole

  voriconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  voriconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

Serious - Use Alternative (39)

• atenolol

  atenolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• betaxolol

  betaxolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• bisoprolol

  bisoprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• celiprolol

  celiprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• dienogest/estradiol valerate

  mavacamten will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• diltiazem

  diltiazem, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• disopyramide

  disopyramide, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• drospirenone

  mavacamten will decrease the level or effect of drospirenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• elacestrant

  mavacamten will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• esmolol

  esmolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• ethinylestradiol

  mavacamten will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• etonogestrel

  mavacamten will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• lenacapavir

  mavacamten will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lenacapavir with moderate CYP3A4 inducers.

• leniolisib

  mavacamten will decrease the level or effect of leniolisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• levonorgestrel intrauterine

  mavacamten will decrease the level or effect of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• levonorgestrel oral

  mavacamten will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  mavacamten will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• medroxyprogesterone

  mavacamten will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• megestrol

  mavacamten will decrease the level or effect of megestrol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• metoprolol

  metoprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• nadolol

  nadolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• nebivolol

  nebivolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• norethindrone

  mavacamten will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norethindrone acetate

  mavacamten will decrease the level or effect of norethindrone acetate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norethindrone transdermal

  mavacamten will decrease the level or effect of norethindrone transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norgestrel

  mavacamten will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• olutasidenib

  mavacamten will decrease the level or effect of olutasidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A inducers decrease olutasidenib (a CYP3A4 substrate) plasma concentrations and efficacy.

• omaveloxolone

  mavacamten will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• penbutolol

  penbutolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• progesterone intravaginal gel

  mavacamten will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• progesterone micronized

  mavacamten will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• propranolol

  propranolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• ranolazine

  ranolazine, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• segesterone/ethinyl estradiol

  mavacamten will decrease the level or effect of segesterone/ethinyl estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• sotalol

  sotalol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• timolol

  timolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• verapamil

  verapamil, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• vonoprazan

  mavacamten will decrease the level or effect of vonoprazan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• zanubrutinib

  mavacamten will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of zanubrutinib (a CYP3A4 substrate) with moderate CYP3A4 inhibitors. If unavoidable, increase zanubrutinib dose to 320 mg PO BID. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.

Monitor Closely (94)

• amiodarone

  amiodarone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• amitriptyline

  amitriptyline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• aprepitant

  aprepitant will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  aprepitant will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• azelastine

  azelastine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• bicalutamide

  bicalutamide will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• brivaracetam

  brivaracetam will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine

  buprenorphine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine buccal

  buprenorphine buccal will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine transdermal

  buprenorphine transdermal will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• ceritinib

  ceritinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• cimetidine

  cimetidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• citalopram

  citalopram will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• clotrimazole

  clotrimazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• clozapine

  clozapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• crizotinib

  crizotinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• cyclosporine

  cyclosporine will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• diazepam

  diazepam will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• diltiazem

  diltiazem will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• divalproex sodium

  divalproex sodium will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• doxycycline

  doxycycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• dronedarone

  dronedarone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• drospirenone

  drospirenone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• elagolix

  elagolix will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• entacapone

  entacapone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  entacapone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin base

  erythromycin base will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin ethylsuccinate

  erythromycin ethylsuccinate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin lactobionate

  erythromycin lactobionate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin stearate

  erythromycin stearate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ethotoin

  ethotoin will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fedratinib

  fedratinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• felbamate

  felbamate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibrate

  fenofibrate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibrate micronized

  fenofibrate micronized will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibric acid

  fenofibric acid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fexinidazole

  fexinidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fluconazole

  fluconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fluvoxamine

  fluvoxamine will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fosamprenavir

  fosamprenavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  fosamprenavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fosaprepitant

  fosaprepitant will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  fosaprepitant will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fostamatinib

  fostamatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• gefitinib

  gefitinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• haloperidol

  haloperidol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ibrexafungerp

  ibrexafungerp will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• iloperidone

  iloperidone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• imatinib

  imatinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  imatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• imipramine

  imipramine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• indinavir

  indinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• indomethacin

  indomethacin will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• isavuconazonium sulfate

  isavuconazonium sulfate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• isoniazid

  isoniazid will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ivacaftor

  ivacaftor will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• lapatinib

  lapatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• larotrectinib

  larotrectinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• lefamulin

  lefamulin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• lenacapavir

  lenacapavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

• lenvatinib

  lenvatinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• letermovir

  letermovir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• letrozole

  letrozole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• losartan

  losartan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• mephobarbital

  mephobarbital will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methimazole

  methimazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methoxsalen

  methoxsalen will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methsuximide

  methsuximide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• metronidazole

  metronidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• nelfinavir

  nelfinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• netupitant/palonosetron

  netupitant/palonosetron will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• nilutamide

  nilutamide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• olanzapine

  olanzapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• orphenadrine

  orphenadrine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• oxcarbazepine

  oxcarbazepine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• paroxetine

  paroxetine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pentamidine

  pentamidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pimozide

  pimozide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pioglitazone

  pioglitazone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• probenecid

  probenecid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• progesterone micronized

  progesterone micronized will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• quinupristin/dalfopristin

  quinupristin/dalfopristin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ribociclib

  ribociclib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• rosiglitazone

  rosiglitazone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• saquinavir

  saquinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• schisandra

  schisandra will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• selegiline

  selegiline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• sertraline

  sertraline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• sildenafil

  sildenafil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• sparsentan

  sparsentan will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C19 inducer) decreases exposure of CYP2C19 substrates and reduces efficacy related to these substrates.

• tecovirimat

  tecovirimat will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• telmisartan

  telmisartan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• tetracycline

  tetracycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• topiramate

  topiramate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• torsemide

  torsemide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• valproic acid

  valproic acid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• vismodegib

  vismodegib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• voxelotor

  voxelotor will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• zafirlukast

  zafirlukast will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

Minor (0)

• abiraterone

  Contraindicated (1)abiraterone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• amiodarone

  Monitor Closely (1)amiodarone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• amitriptyline

  Monitor Closely (1)amitriptyline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• amobarbital

  Contraindicated (1)amobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• apalutamide

  Contraindicated (2)apalutamide will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  apalutamide will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• aprepitant

  Monitor Closely (2)aprepitant will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  aprepitant will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• armodafinil

  Contraindicated (2)armodafinil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  armodafinil will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• atazanavir

  Contraindicated (1)atazanavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• atenolol

  Serious - Use Alternative (1)atenolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• azelastine

  Monitor Closely (1)azelastine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• belzutifan

  Contraindicated (1)belzutifan will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• betaxolol

  Serious - Use Alternative (1)betaxolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• bexarotene

  Contraindicated (1)bexarotene will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• bicalutamide

  Monitor Closely (1)bicalutamide will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• bisoprolol

  Serious - Use Alternative (1)bisoprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• bortezomib

  Contraindicated (1)bortezomib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• bosentan

  Contraindicated (1)bosentan will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• brivaracetam

  Monitor Closely (1)brivaracetam will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine

  Monitor Closely (1)buprenorphine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine buccal

  Monitor Closely (1)buprenorphine buccal will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• buprenorphine transdermal

  Monitor Closely (1)buprenorphine transdermal will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• butabarbital

  Contraindicated (1)butabarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• butalbital

  Contraindicated (1)butalbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• cannabidiol

  Contraindicated (1)cannabidiol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• carbamazepine

  Contraindicated (2)carbamazepine will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  carbamazepine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• celiprolol

  Serious - Use Alternative (1)celiprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• cenobamate

  Contraindicated (2)cenobamate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  cenobamate will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ceritinib

  Monitor Closely (1)ceritinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• chloramphenicol

  Contraindicated (2)chloramphenicol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  chloramphenicol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• cimetidine

  Monitor Closely (1)cimetidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• citalopram

  Monitor Closely (1)citalopram will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• clarithromycin

  Contraindicated (1)clarithromycin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• clotrimazole

  Monitor Closely (1)clotrimazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• clozapine

  Monitor Closely (1)clozapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• cobicistat

  Contraindicated (1)cobicistat will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• conivaptan

  Contraindicated (1)conivaptan will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• crizotinib

  Monitor Closely (1)crizotinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• cyclosporine

  Monitor Closely (1)cyclosporine will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• dabrafenib

  Contraindicated (2)dabrafenib will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  dabrafenib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• darunavir

  Contraindicated (1)darunavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• delavirdine

  Contraindicated (1)delavirdine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• dexlansoprazole

  Contraindicated (1)dexlansoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• diazepam

  Monitor Closely (1)diazepam will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• dienogest/estradiol valerate

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• diltiazem

  Monitor Closely (1)diltiazem will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose. Serious - Use Alternative (1)diltiazem, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• disopyramide

  Serious - Use Alternative (1)disopyramide, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• divalproex sodium

  Monitor Closely (1)divalproex sodium will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• doxycycline

  Monitor Closely (1)doxycycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• dronedarone

  Monitor Closely (1)dronedarone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• drospirenone

  Monitor Closely (1)drospirenone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose. Serious - Use Alternative (1)mavacamten will decrease the level or effect of drospirenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• efavirenz

  Contraindicated (2)efavirenz will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  efavirenz will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• elacestrant

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• elagolix

  Contraindicated (1)elagolix will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (1)elagolix will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Contraindicated (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• encorafenib

  Contraindicated (1)encorafenib decreases levels of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• entacapone

  Monitor Closely (2)entacapone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  entacapone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• enzalutamide

  Contraindicated (2)enzalutamide will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  enzalutamide will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• erythromycin base

  Monitor Closely (1)erythromycin base will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin ethylsuccinate

  Monitor Closely (1)erythromycin ethylsuccinate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin lactobionate

  Monitor Closely (1)erythromycin lactobionate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• erythromycin stearate

  Monitor Closely (1)erythromycin stearate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• eslicarbazepine acetate

  Contraindicated (2)eslicarbazepine acetate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  eslicarbazepine acetate will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• esmolol

  Serious - Use Alternative (1)esmolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• esomeprazole

  Contraindicated (1)esomeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• ethinylestradiol

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• ethotoin

  Monitor Closely (1)ethotoin will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• etonogestrel

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• etravirine

  Contraindicated (2)etravirine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  etravirine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• fedratinib

  Contraindicated (1)fedratinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)fedratinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• felbamate

  Monitor Closely (1)felbamate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibrate

  Monitor Closely (1)fenofibrate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibrate micronized

  Monitor Closely (1)fenofibrate micronized will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fenofibric acid

  Monitor Closely (1)fenofibric acid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• fexinidazole

  Contraindicated (1)fexinidazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)fexinidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fluconazole

  Contraindicated (1)fluconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)fluconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fluoxetine

  Contraindicated (1)fluoxetine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• fluvoxamine

  Contraindicated (1)fluvoxamine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)fluvoxamine will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fosamprenavir

  Monitor Closely (2)fosamprenavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  fosamprenavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fosaprepitant

  Monitor Closely (2)fosaprepitant will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  fosaprepitant will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• fosphenytoin

  Contraindicated (2)fosphenytoin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  fosphenytoin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• fostamatinib

  Monitor Closely (1)fostamatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• gefitinib

  Monitor Closely (1)gefitinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• gemfibrozil

  Contraindicated (1)gemfibrozil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• grapefruit

  Contraindicated (1)grapefruit will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• haloperidol

  Monitor Closely (1)haloperidol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ibrexafungerp

  Monitor Closely (1)ibrexafungerp will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• idelalisib

  Contraindicated (1)idelalisib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• iloperidone

  Monitor Closely (1)iloperidone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• imatinib

  Monitor Closely (2)imatinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
  
  imatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• imipramine

  Monitor Closely (1)imipramine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• indinavir

  Contraindicated (1)indinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)indinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• indomethacin

  Monitor Closely (1)indomethacin will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• isavuconazonium sulfate

  Monitor Closely (1)isavuconazonium sulfate will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• isoniazid

  Contraindicated (1)isoniazid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)isoniazid will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• itraconazole

  Contraindicated (1)itraconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• ivacaftor

  Monitor Closely (1)ivacaftor will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ivosidenib

  Contraindicated (1)ivosidenib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ketoconazole

  Contraindicated (2)ketoconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  ketoconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lansoprazole

  Contraindicated (1)lansoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lapatinib

  Monitor Closely (1)lapatinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• larotrectinib

  Monitor Closely (1)larotrectinib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• lefamulin

  Monitor Closely (1)lefamulin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• lenacapavir

  Monitor Closely (1)lenacapavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.Serious - Use Alternative (1)mavacamten will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lenacapavir with moderate CYP3A4 inducers.

• leniolisib

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of leniolisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lenvatinib

  Monitor Closely (1)lenvatinib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• letermovir

  Monitor Closely (1)letermovir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• letrozole

  Monitor Closely (1)letrozole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• levoketoconazole

  Contraindicated (1)levoketoconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• levonorgestrel intrauterine

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• levonorgestrel oral

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• lonafarnib

  Contraindicated (2)lonafarnib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  lonafarnib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lopinavir

  Contraindicated (2)lopinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  lopinavir will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.

• loratadine

  Contraindicated (1)loratadine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• lorlatinib

  Contraindicated (1)lorlatinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• losartan

  Monitor Closely (1)losartan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• lumacaftor/ivacaftor

  Contraindicated (1)lumacaftor/ivacaftor will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• medroxyprogesterone

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• megestrol

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of megestrol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• mephobarbital

  Monitor Closely (1)mephobarbital will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methimazole

  Monitor Closely (1)methimazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methoxsalen

  Monitor Closely (1)methoxsalen will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• methsuximide

  Monitor Closely (1)methsuximide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• metoprolol

  Serious - Use Alternative (1)metoprolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• metronidazole

  Monitor Closely (1)metronidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• mifepristone

  Contraindicated (1)mifepristone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• mitapivat

  Contraindicated (2)mitapivat will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  mitapivat will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• mitotane

  Contraindicated (1)mitotane will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• mobocertinib

  Contraindicated (1)mobocertinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• modafinil

  Contraindicated (2)modafinil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  modafinil will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nadolol

  Serious - Use Alternative (1)nadolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• nafcillin

  Contraindicated (1)nafcillin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nebivolol

  Serious - Use Alternative (1)nebivolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• nefazodone

  Contraindicated (1)nefazodone will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• nelfinavir

  Contraindicated (1)nelfinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)nelfinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• netupitant/palonosetron

  Monitor Closely (1)netupitant/palonosetron will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• nicardipine

  Contraindicated (1)nicardipine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• nilutamide

  Monitor Closely (1)nilutamide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• nirmatrelvir/ritonavir

  Contraindicated (1)nirmatrelvir/ritonavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• norethindrone

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norethindrone acetate

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of norethindrone acetate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norethindrone transdermal

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of norethindrone transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• norgestrel

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• olanzapine

  Monitor Closely (1)olanzapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• olutasidenib

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of olutasidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A inducers decrease olutasidenib (a CYP3A4 substrate) plasma concentrations and efficacy.

• omaveloxolone

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• omeprazole

  Contraindicated (1)omeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• orphenadrine

  Monitor Closely (1)orphenadrine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• oxcarbazepine

  Monitor Closely (1)oxcarbazepine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pantoprazole

  Contraindicated (1)pantoprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• paroxetine

  Monitor Closely (1)paroxetine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• penbutolol

  Serious - Use Alternative (1)penbutolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• pentamidine

  Monitor Closely (1)pentamidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pentobarbital

  Contraindicated (1)pentobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• pexidartinib

  Contraindicated (1)pexidartinib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• phenobarbital

  Contraindicated (1)phenobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• phenytoin

  Contraindicated (2)phenytoin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  phenytoin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• pimozide

  Monitor Closely (1)pimozide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• pioglitazone

  Monitor Closely (1)pioglitazone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• posaconazole

  Contraindicated (1)posaconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• primidone

  Contraindicated (1)primidone will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• probenecid

  Monitor Closely (1)probenecid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• progesterone intravaginal gel

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• progesterone micronized

  Monitor Closely (1)progesterone micronized will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose. Serious - Use Alternative (1)mavacamten will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• propofol

  Contraindicated (1)propofol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• propranolol

  Serious - Use Alternative (1)propranolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• quinupristin/dalfopristin

  Monitor Closely (1)quinupristin/dalfopristin will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• rabeprazole

  Contraindicated (1)rabeprazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• ranolazine

  Serious - Use Alternative (1)ranolazine, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• ribociclib

  Monitor Closely (1)ribociclib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• rifabutin

  Contraindicated (1)rifabutin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• rifampin

  Contraindicated (2)rifampin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  rifampin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• rifapentine

  Contraindicated (1)rifapentine will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ritonavir

  Contraindicated (1)ritonavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• rosiglitazone

  Monitor Closely (1)rosiglitazone will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• rucaparib

  Contraindicated (2)rucaparib will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  rucaparib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• saquinavir

  Contraindicated (1)saquinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)saquinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• schisandra

  Monitor Closely (1)schisandra will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• secobarbital

  Contraindicated (1)secobarbital will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• segesterone/ethinyl estradiol

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of segesterone/ethinyl estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may decrease systemic exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or an increase in breakthrough bleeding. Advise patients to use a contraceptive method that is not affected by CYP450 enzyme induction (eg, intrauterine system) or add nonhormonal contraception (eg, condoms) during coadministration and for 4 months after last mavacamten dose.

• selegiline

  Monitor Closely (1)selegiline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• sertraline

  Contraindicated (1)sertraline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)sertraline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• sildenafil

  Monitor Closely (1)sildenafil will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• sitaxentan

  Contraindicated (1)sitaxentan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• sotalol

  Serious - Use Alternative (1)sotalol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• sotorasib

  Contraindicated (1)sotorasib will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• sparsentan

  Monitor Closely (1)sparsentan will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C19 inducer) decreases exposure of CYP2C19 substrates and reduces efficacy related to these substrates.

• St John's Wort

  Contraindicated (1)St John's Wort will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• stiripentol

  Contraindicated (2)stiripentol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  stiripentol will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• tecovirimat

  Monitor Closely (1)tecovirimat will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• telmisartan

  Monitor Closely (1)telmisartan will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• telotristat ethyl

  Contraindicated (1)telotristat ethyl will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• tetracycline

  Monitor Closely (1)tetracycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• ticlopidine

  Contraindicated (1)ticlopidine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• timolol

  Serious - Use Alternative (1)timolol, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• tipranavir

  Contraindicated (1)tipranavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• topiramate

  Monitor Closely (1)topiramate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• torsemide

  Monitor Closely (1)torsemide will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• tranylcypromine

  Contraindicated (1)tranylcypromine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• triclabendazole

  Contraindicated (1)triclabendazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• valproic acid

  Monitor Closely (1)valproic acid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• verapamil

  Serious - Use Alternative (1)verapamil, mavacamten. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Expect additive negative inotropic effects of mavacamten and other drugs that reduce cardiac contractility.

• vismodegib

  Monitor Closely (1)vismodegib will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• vonoprazan

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of vonoprazan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• voriconazole

  Contraindicated (2)voriconazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
  
  voriconazole will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• voxelotor

  Monitor Closely (1)voxelotor will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• zafirlukast

  Monitor Closely (1)zafirlukast will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• zanubrutinib

  Serious - Use Alternative (1)mavacamten will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of zanubrutinib (a CYP3A4 substrate) with moderate CYP3A4 inhibitors. If unavoidable, increase zanubrutinib dose to 320 mg PO BID. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.