Animal studies with this product have not been reported. There are no controlled data in human pregnancy.

AMOXICILLIN: Animal studies have failed to reveal evidence of fetal harm; studies were performed in mice and rats at doses up to 2000 mg/kg (5 and 10 times the 2 g human dose, respectively, and 3 and 6 times the 3 g human dose, respectively, based on body surface area [BSA] comparison). There are no controlled data in human pregnancy.

VONOPRAZAN: Animal studies have revealed evidence of embryofetal toxicity, teratogenicity, and embryofetal mortality at exposures higher than the maximum recommended human dose [MRHD] based on AUC comparison. After oral dosing to pregnant rats at doses of 30, 100, or 300 mg/kg/day (7, 27, 130 times MRHD based on AUC comparison at the same doses from unmated female rats from separate studies) during organogenesis (GB 6 to 17), 1 high-dose female died and decreased body weight and food intake occurred at the middle and highest doses; no embryofetal lethality and no adverse embryofetal effects were observed in the highest dose group and at 100 mg/kg/day, respectively, but decreased fetal body weight was seen in the highest dose group and fetal abnormalities were limited to the 300 mg/kg/day dose group. After oral dosing to pregnant rabbits at doses of 3, 10, or 30 mg/kg/day (0.04, 1.5, 10 times MRHD based on AUC comparison) during organogenesis (GD 6 to 18), 2 animals aborted at the highest dose and decreased body weight and food intake; no embryofetal mortality or toxicity occurred and there were no external, visceral, or skeletal abnormalities. 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 product is not recommended unless there are no alternatives.

US FDA pregnancy category: Not assigned.

Risk summary: No data available on use of this product in pregnant women to inform a drug-related risk.

Comments:
-Pregnancies should be reported to Phathom Pharmaceuticals at 1-888-775-7428.

See references

Breastfeeding is not recommended during use of this product and for 2 days after the last dose.

Excreted into human milk: Yes (amoxicillin); Unknown (vonoprazan)
Excreted into animal milk: Yes (vonoprazan)

Comments:
-No information is available on the clinical use of vonoprazan during breastfeeding; an alternate drug may be preferred.
-Due to the potential risk of adverse liver effects shown in animal studies with vonoprazan, women should pump and discard human milk during therapy and for 2 days after the last dose; infants should be fed stored human milk (collected before therapy) or formula.
-Amoxicillin is considered acceptable in nursing mothers.

AMOXICILLIN:
Limited information indicates amoxicillin produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Rash and disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) have been reported occasionally; such effects have not been adequately evaluated.

After a single 1 g oral dose in 6 women, peak milk amoxicillin levels occurred at 4 to 5 hours after dosing; milk levels averaged 0.69 mg/L (range: 0.46 to 0.88 mg/L) at 4 hours and 0.81 mg/L (range: 0.39 to 1.3 mg/L) at 5 hours after dosing. From this data, it is expected that an exclusively breastfed infant would receive a maximum of about 0.1 mg/kg/day with a maternal dose of 500 mg 3 times a day (about 0.25% to 0.5% of a typical infant amoxicillin dose).

In a telephone follow-up study, 25 nursing mothers reported taking amoxicillin (dosage not provided); while 3 mothers reported diarrhea in their infants, no rashes or candidiasis were reported in the exposed infants. A prospective, controlled study asked mothers who called an information service about adverse reactions experienced by their breastfed infants; of 40 infants exposed to amoxicillin in breast milk, 2 developed diarrhea and 1 developed a rash.

A study compared breastfed infants of mothers taking amoxicillin to those taking a macrolide antibiotic. Adverse reactions occurred in 8.3% of the infants exposed to amoxicillin, which was similar to the rate in macrolide-exposed infants; reactions included rash and somnolence.

See references