Paxlovid Use In Pregnancy & Lactation

Women of childbearing potential/Contraception in males and females: There are limited human data on the use of PAXLOVID during pregnancy to inform the drug-associated risk of adverse developmental outcomes; women of childbearing potential should avoid becoming pregnant during treatment with PAXLOVID and for 7 days after completing PAXLOVID treatment.
Use of ritonavir may reduce the efficacy of combined hormonal contraceptives. Patients using combined hormonal contraceptives should be advised to use an effective alternative contraceptive method or an additional barrier method of contraception during treatment with PAXLOVID, and until one menstrual cycle after stopping PAXLOVID (see Interactions).
Pregnancy: There are limited data from the use of PAXLOVID in pregnant women. PAXLOVID should be used during pregnancy only if the potential benefits outweigh the potential risks for the mother and the fetus.
Animal data with nirmatrelvir have shown developmental toxicity in the rabbit (lower fetal body weights) but not in the rat. There was no nirmatrelvir-related effect on fetal morphology or embryo-fetal viability at any dose tested in rat or rabbit embryo-fetal developmental toxicity studies. There were no nirmatrelvir-related adverse effects in a pre- and postnatal developmental study in rats (see Pharmacology: Toxicology: Preclinical safety data under Actions).
A large number (6,100 live births) of pregnant women were exposed to ritonavir during pregnancy; of these, 2,800 live births were exposed during the first trimester. These data largely refer to exposures where ritonavir was used in combination therapy and not at therapeutic ritonavir doses but at lower doses as a PK enhancer for other protease inhibitors, similar to the ritonavir dose used for nirmatrelvir/ritonavir. These data indicate no increase in the rate of birth defects compared to rates observed in population-based birth defect surveillance systems.
Animal data with ritonavir have shown reproductive toxicity (see Pharmacology: Toxicology: Preclinical safety data under Actions).
Breast-feeding: In a clinical pharmacokinetics study, 8 healthy lactating women who were at least 12 weeks postpartum were administered 3 doses (steady-state dosing) of 300 mg/100 mg nirmatrelvir/ritonavir. Nirmatrelvir and ritonavir were excreted in breast milk in small amounts, with a milk to plasma AUC ratio of 0.26 and 0.07, respectively. The estimated daily infant dose (assuming average milk consumption of 150 mL/kg/day), was 1.8% and 0.2% of the maternal dose.
There are no available data on the effects of nirmatrelvir or ritonavir on the breast-fed newborn/infant or on milk production. A risk to the newborn/infant cannot be excluded. Breast-feeding should be discontinued during treatment with PAXLOVID and for 48 hours after completing PAXLOVID treatment.
Fertility: There are no human data on the effect of PAXLOVID on fertility. No human data on the effect of nirmatrelvir on fertility are available. Nirmatrelvir produced no effects on fertility in rats (see Pharmacology: Toxicology: Preclinical safety data under Actions).
There are no human data on the effect of ritonavir on fertility. Ritonavir produced no effects on fertility in rats.