Animal studies have failed to reveal evidence of fetal harm. Controlled data in human pregnancy have not associated use of this drug during pregnancy with major birth defect, miscarriage, or adverse maternal/fetal outcomes.

In 2 controlled studies, this drug was used to treat Schistosoma infection in pregnant women. In 1 study, this drug was used in 186 pregnant women; therapy had no effect on birth weight and rates of miscarriage, fetal death, and major birth defects did not differ between this drug and placebo. In another study that included 2507 pregnant women, 18% were infected with Schistosoma; treatment with this drug during pregnancy had no effect on average birth weight, perinatal mortality, or major birth defects.

In other studies (including a retrospective observational study, case series, case reports), no reports of major birth defects, stillbirths, or other adverse pregnancy outcomes have been associated with use of this drug during pregnancy.

AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

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 be used during pregnancy only if clearly needed.

AU TGA pregnancy category: B1
US FDA pregnancy category: Not assigned.

Risk summary: Malformative risk with use of this drug in pregnant women is unlikely.

See references

Use is considered acceptable; breastfeeding should not be a contraindication to maternal treatment.

Excreted into human milk: Yes (small amounts)

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. Side effects from this drug not expected due to minute levels in breast milk.
-To reduce infant exposure, a single dose can be taken just before the infant's longest sleep period or an alternative method of feeding (e.g., stored human milk, formula) can be used for 24 to 36 hours after a single (or the last) dose.

After a single oral dose (about 50 mg/kg) in 5 women, peak milk level averaged 440 mcg/L about 2 hours after dosing (6 hours after dosing in 1 woman); by 24 hours after dosing, the drug was undetectable (less than 4 mcg/L) in 4 women and near the lower limit of detection (6 mcg/L) in the other woman. According to author calculation, the amount excreted into milk in 24 hours averaged 27 mcg (range: 6.8 to 75 mcg), corresponding to 0.0087% of the total (not weight-adjusted) dose.

In the same paper, another 5 women were given 20 mg/kg orally every 4 hours for 3 doses. With this regimen, peaks of 250 and 460 mcg/L were observed 4 and 10 hours after the first dose, respectively; a meal near the second dose probably delayed its absorption. According to author calculation, the amount excreted into milk in 24 hours averaged 25.6 mcg (range: 4.6 to 49 mcg), corresponding to 0.0007% of the total (not weight-adjusted) dose.

A pharmacokinetic model of drug excretion into milk was created using data from the above studies. The model predicted a half-life of about 1 hour for this drug in milk.

Human milk drug levels were about 25% of the levels in maternal serum. The mean excretion of this drug in milk, in 10 lactating women, was less than 0.1% of the dose.

According to some authorities: Women should not breastfeed on the day of treatment and during the subsequent 72 hours.

See references