Use is contraindicated.

AU TGA pregnancy category: X
US FDA pregnancy category: Not assigned.

Risk Summary: This drug may cause fetal harm when administered to a pregnant woman.

Comments:
-If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus and patient options.
-Pregnancy testing should be performed before the initiation of treatment, monthly while on treatment, and 1 month after stopping treatment.
-Acceptable methods of contraception should be used during treatment and for 1 month after stopping treatment.
-Acceptable methods of contraception include 1 highly effective form (intrauterine device (IUD), contraceptive implant, or tubal sterilization) or a combination of methods (hormone method with a barrier method or 2 barrier methods); if a partner's vasectomy is decided as 1 method of contraception, a hormone or barrier method should also be used.
-Counsel patients on pregnancy planning and prevention, including emergency contraception.
-Some authorities recommend pregnancy prevention for at least 3 months after stopping treatment.

Animal studies have revealed evidence of teratogenicity at a dose 1.7 times the human dose of 10 mg per day based on AUC. There are limited data in human pregnancy.

The effect of this drug on male human fertility is unknown, but it appears endothelin receptor antagonists may have an adverse effect on spermatogenesis. In a 6-month clinical trial with bosentan, another endothelin receptor antagonist, a decline in sperm count of at least 50% was observed in at least 25% of patients after 3 to 6 months; however, in 22 of 25 patients who completed 6 months of treatment, sperm count remained within normal limits with no changes in sperm morphology, sperm motility, or hormone levels.

AU TGA pregnancy category X: Drugs which have such a high risk of causing permanent damage to the fetus that they should not be used in pregnancy or when there is a possibility of pregnancy.

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.

See references

(UK) Use is contraindicated.
(AU, US) A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

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

Comments: The effects in the nursing infant are unknown.

See references