Animal studies have revealed evidence of embryofetal toxicity and fetal malformations. After oral administration to pregnant rats at 40 mg/kg/day (0.6 times the 600 mg human dose based on body surface area [BSA] comparisons) during organogenesis, cleft palates, malpositioned aortic arches, delayed ossification, increased number of ribs, decreased litter size and mean litter weight, increased number of stillbirths, and increased mortality during lactation were observed; decreased pup weights, decreased gestational survival, increased resorptions, postimplantation loss, decreased mean fetal weight, increased numbers of stillborn pups, and slightly increased pup mortality during lactation were noted after oral administration to rats at 20 mg/kg/day (0.3 times the human dose based on BSA) late in gestation. After oral administration to pregnant rabbits at 10 to 40 mg/kg (0.3 to 1.3 times the human dose based on BSA) during organogenesis, major fetal malformations occurred (including ovarian agenesis, pes varus, arrhinia, microphthalmia, ossified facial tissue irregularities); at 40 mg/kg/day, increased postimplantation loss and increased incidence of stillborn pups were observed. There are no controlled data in human 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.

This drug should not be used during pregnancy unless the benefit outweighs the risk to the fetus.

US FDA pregnancy category: Not assigned

Risk summary: Based on animal data, this drug may cause fetal harm; insufficient data available on use of this drug in pregnant women to inform a drug-related risk.

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.
-Disease-associated maternal and/or embryofetal risk should be considered; active tuberculosis in pregnancy is associated with adverse maternal and neonatal outcomes (including maternal anemia, cesarean delivery, preterm birth, low birth weight, birth asphyxia, perinatal infant death).
-When used during the last few weeks of pregnancy, this drug may increase the risk for maternal postpartum hemorrhage and bleeding in the exposed neonate. Prothrombin time should be monitored in pregnant women and neonates exposed to this drug during the last few weeks of pregnancy; treatment with vitamin K may be indicated.
-This drug may reduce the efficacy of hormonal contraceptives; patients using hormonal contraceptives should be advised to use an alternative nonhormonal contraceptive method or add a barrier method of contraception during therapy.

See references

Benefit should outweigh risk.

Excreted into human milk: Yes

Comments:
-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.
-This drug may produce a red-orange discoloration of breast milk.
-Infants exposed to this drug through breast milk should be monitored for signs of hepatotoxicity to include irritability, prolonged unexplained crying, yellowing of the eyes, loss of appetite, vomiting, and darkening urine/lightening stool (pale or light brown).
-The American Academy of Pediatrics considers rifampin (rifampicin), a closely related agent, compatible with breastfeeding.
-The US CDC and other experts state that breastfeeding should not be discouraged in patients taking this drug.

The amount of this drug and its metabolite in milk is insufficient to treat tuberculosis in the breastfed infant.

In a study of pregnant and postpartum women with latent tuberculosis infection, patients received 12 directly observed once-weekly doses of rifapentine 900 mg, isoniazid 900 mg, and pyridoxine 25 to 100 mg. In 22 women who donated milk samples, rifapentine milk levels averaged about 280 mcg/L at 3 hours after the first dose, 533 mcg/L at 6 hours after the second dose, and 293 mcg/L at 24 hours after the last dose; milk levels of the metabolite (25-desacetyl rifapentine) averaged about 67 mcg/L at 3 hours after the first dose, 180 mcg/L at 6 hours after the second dose, and 360 mcg/L at 24 hours after the last dose.

See references