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Cimetidine has weak antiandrogenic effects in animals and antiandrogenic effects in humans, causing impotence and oligospermia (Sawyer et al., 1981)
. Antiandrogenic effects have not been seen with the use of ranitidine (Parker et al.,1984).
Proton Pump Inhibitors (PPIs)
Proton pump inhibitors decrease the stomach’s production of acid more completely than the H2RA’s by stopping the stomach’s acid pump, which is the final step of acid secretion. PPIs are a relatively new class of GERD treatment, and as such, less information is available.
Lansoprazole (Prevacid)
Animal studies on lansoprazole in rabbits and rats did not find evidence that lansoprazole impairs fertility or teratogenicity at 16 to 80 times the human doses, respectively (Schardein et al., 1990; Briggs et al., 1998). There have been no reports on the effects of lansoprazole use during human pregnancy, and as such its risk is undetermined.
Omeprazole (Prilosec)
Animals given up to 345 times the recommended human dose of omeprazole did not show teratogenic effects, although there was a slight increase in miscarriage and fetal mortality (Briggs et al., 1990). A case report of a woman who used omeprazole in three pregnancies, including one in the first trimester, showed that she delivered three healthy infants (Harper et al., 1995). Several case reports exist of adverse outcomes after omeprazole use. The FDA has received 11 voluntary reports of birth defects following pregnancy exposure to omeprazole use, including four cases of anencephaly and one case of hydranencephaly after use in the second trimester (Briggs et al., 1998). Tsirigotis et al. (1995) describes a woman who ingested 20mg of omeprazole daily during two consecutive pregnancies and subsequently terminated them because of anencephaly and clubfoot, respectively. While these case reports of anencephaly suggest a pattern of defects, without background information on these pregnancies, the potential confounding factors inherent in case reports make it difficult to attribute the cause to omeprazole.
In a recent prospective cohort study of 113 women exposed to omeprazole, 101 throughout organogenesis (89%) and 15% throughout pregnancy, no association was found between in utero exposure and malformations, birth weight, gestational age at delivery, preterm deliveries, or neonatal complications (Lalkin et al., 1998). Although the case reports may be concerning, the lack of teratogenicity in animals and the recent prospective human studies show that omeprazole is unlikely to significantly increase the risk for birth defects.
Prokinetic Agents
Prokinetic agents hasten emptying of the stomach contents, resulting in less acid secretion available for reflux. Some agents also increase the "tone" of the lower esophageal sphincter, making it more difficult to open.
Cisapride (Propulsid)
Animal studies in rats show impaired fertility at 25 times the human dose. At 12 to 100 times the human dose in rats and rabbits, respectively, an increase in IUGR and neonatal death was noted (Briggs et al., 1998). In a prospective study, 129 pregnant women were exposed to cisapride, including 88 during organogenesis. There were no differences in birthweight, gestational age at delivery, and rates of livebirths, spontaneous abortions, fetal distress, and major or minor malformations among those exposed to the drug and those used in the control group. This suggests that cisapride is not likely to pose a significant teratogenic risk (Bailey et al., 1997).
Metoclopramide (Reglan)
Manufacturer's information on mice, rats, and rabbits given doses up to 250 times the human dose, showed no evidence of fetal harm (Briggs et al., 1998). In a retrospective study of 192 newborns exposed to metoclopramide in the first trimester, 10 (5.2%) major birth defects were seen (Briggs et al., 1998). In a study by Nageotte et al. (1996) 80 women with hyperemesis used metoclopramide during pregnancy. Three women who used metoclopromide in the second trimester delivered infants with birth defects; there was no pattern to the defects, making it even less likely that metoclopramide was a causal factor. Five case reports of women exposed to metoclopramide in early pregnancy did not show teratogenic effects (Briggs et al., 1998).