Pregnancy Category C

Risk Summary

There are no adequate and well controlled studies of esomeprazole strontium delayed-release capsules in pregnant women. Teratogenicity was not observed in an embryofetal developmental study in rats with either esomeprazole strontium or esomeprazole magnesium at equimolar oral doses up to 280 mg esomeprazole/kg/day (about 57 times the daily maximum recommended human dose (MRHD) of 40 mg on a body surface area basis). When administered as either the strontium or magnesium salt, changes in bone morphology and physeal dysplasia were observed in pre- and postnatal developmental toxicity studies in rats at doses equal to or greater than 138 mg esomeprazole/kg/day (approximately 33.6 times the daily MRHD of 40 mg on a body surface area basis). Because of the observed effect at the high doses of esomeprazole strontium on developing bone in rat studies, esomeprazole strontium should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. 

Animal Data

An embryofetal developmental (teratogenicity) study in rats was performed with both esomeprazole strontium and esomeprazole magnesium at equimolar oral doses of 14 to 280 mg esomeprazole/kg/day (about 3.4 to 57 times the daily maximum recommended human dose (MRHD) of 40 mg, on a body surface area basis). At the doses tested, there were no teratogenic or adverse effects on general fetal development or on fetal visceral or skeletal structures. In addition, there was no adverse effect on maternal and fetal bone calcium levels when esomeprazole was administered as either the strontium or magnesium salt. Fetal exposure to strontium and esomeprazole was dose-related. 

Pre- and postnatal developmental toxicity studies in rats with additional endpoints to evaluate bone development were performed with both esomeprazole strontium and esomeprazole magnesium at equimolar oral doses of 14 to 280 mg esomeprazole/kg/day (about 3.4 to 57 times the daily MRHD of 40 mg of esomeprazole on a body surface area basis). The rats were fed either a standard diet or a diet with reduced levels of calcium and Vitamin D. When administered as either the strontium or magnesium salt, neonatal/early postnatal (birth to weaning) survival was decreased, body weight and body weight gain were reduced and neurobehavioral or general developmental delays in the immediate post-weaning timeframe were evident at doses equal to or greater than 69 mg esomeprazole/kg/day (about 16.8 times the daily MRHD of 40 mg on a body surface area basis). In addition, when administered as either the strontium or magnesium salt, decreased femur length, width and thickness of cortical bone, decreased thickness of the tibial growth plate and minimal to mild bone marrow hypocellularity were noted at doses equal to or greater than 14 mg esomeprazole/kg/day (about 3.4 times the MRHD of 40 mg on a body surface area basis). Physeal dysplasia in the femur was observed in offspring of rats treated with oral doses of esomeprazole (as either the strontium or the magnesium salt) at doses equal to or greater than 138 mg/kg/day (about 33.6 times the daily MRHD of 40 mg on a body surface area basis). No significant differences were observed between the groups fed nutritionally complete diet and those fed the diet with reduced levels of calcium and Vitamin D.

Adverse effects on maternal bone were observed in pregnant and lactating rats in the pre- and postnatal toxicity studies when esomeprazole strontium or esomeprazole magnesium were administered at equimolar oral doses of 14 to 280 mg esomeprazole/kg/day (about 3.4 to 57 times the daily MRHD of 40 mg on a body surface area basis). When rats were dosed from gestational day 7 through weaning on postnatal day 21, a statistically significant decrease in maternal femur weight of up to 14% (as compared to placebo treatment) was observed at doses equal to or greater than 138 mg esomeprazole/kg/day (about 33.6 times the daily MRHD of 40 mg on a body surface area basis).