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Mavacamten Pregnancy and Breastfeeding Warnings

Brand names: Camzyos

Medically reviewed by Last updated on Oct 10, 2022.

Mavacamten Pregnancy Warnings

Animal studies have revealed evidence of embryolethality, fetotoxicity, and teratogenicity. After oral administration to pregnant rats (0.3 to 1.5 mg/kg/day) during organogenesis, increased postimplantation loss, decreased mean fetal body weight, reduced fetal ossification of bones, and fetal malformations occurred in the high dose group (1.5 mg/kg/day); visceral malformations and increased incidences of skeletal malformations were seen at a similar exposure as in humans at the maximum recommended human dose (MRHD). After oral administration to pregnant rabbits (0.6 to 2 mg/kg/day) during organogenesis, fetal malformations (visceral and skeletal) were increased at doses 1.2 mg/kg/day and higher, with similar plasma exposure at 1.2 mg/kg/day as in humans at the MRHD. Plasma exposure (based on AUC) at the no-effect dose for embryofetal development was 0.3 (rats) and 0.4 (rabbits) times the exposure in humans at the MRHD. There are no controlled data in human pregnancy.

There is a pregnancy safety study for this drug; if this drug is administered during pregnancy, or if a patient becomes pregnant while receiving this drug or within 4 months after the last dose, health care providers should report this drug exposure by contacting Bristol-Myers Squibb at 1-800-721-5072 or

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

The manufacturer makes no recommendation regarding use during pregnancy.

US FDA pregnancy category: Not assigned.

Risk summary: Based on animal data, this drug may cause fetal harm; no data available on use of this drug in pregnant women to inform a drug-related risk.

-A pregnancy exposure registry is available.
-The underlying maternal condition (obstructive hypertrophic cardiomyopathy) during pregnancy poses a risk to mother and fetus; it has been associated with increased risk for preterm birth.
-Pregnant patients should be apprised of the potential harm to the fetus with maternal exposure to this drug during pregnancy.
-Patients of childbearing potential:
---The absence of pregnancy should be confirmed before starting this drug.
---Patients should be advised to use effective contraception during therapy and for 4 months after the last dose; since this drug may reduce the efficacy of combined hormonal contraceptives (CHCs), patients using CHCs should be advised to use an alternative contraceptive method or add nonhormonal contraception.

See references

Mavacamten Breastfeeding Warnings

The manufacturer makes no recommendation regarding use during lactation.

Excreted into human milk: Unknown
Excreted into animal milk: Unknown

-Developmental and health benefits of breastfeeding should be considered as well as the mother's clinical need for this drug.
-The effects in the nursing infant are unknown; potential side effects in the breastfed child due to this drug or the mother's underlying condition should be considered.

See references

References for pregnancy information

  1. Product Information. Camzyos (mavacamten). MyoKardia Inc. 2022.

References for breastfeeding information

  1. Product Information. Camzyos (mavacamten). MyoKardia Inc. 2022.

Further information

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