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Bupropion use during pregnancy has been inadequately studied, making it difficult to compare risks vs. benefits of use in pregnant smokers. No data are available on varenicline use during pregnancy.



dequate and well-controlled studies of bupropion have not been conducted in pregnant women (Benowitz & Dempsey, 2004). Bupropion has a US Food and Drug Administration Pregnancy Category C designation. Category C indicates that animal reproductive studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but the potential benefits may warrant the use of the drug in pregnant women despite potential risk. Animal reproductive studies at doses up to 450 mg/kg in rats (approximately 14-times the maximum recommended human dose [MRHD] on a mg/m² basis) and at doses up to 150 mg/kg in rabbits (approximately 10-times the MRHD on a mg/m² basis) have revealed no evidence of impaired fertility or harm to the foetus due to bupropion.

GlaxoSmithKline manages a pregnancy registry as part of an ongoing programme in epidemiologic safety monitoring. The registry is intended to supplement animal toxicology data, and to assist clinicians in weighing the risks and benefits of treatment for individual patients (http://pregnancyregistry.gsk.com/bupropion.html). The Bupropion Pregnancy Registry Interim Report summarizes prospectively collected pregnancy outcomes from September 1 1997 through August 31, 2007. To date, 1,575 pregnancies involving exposure to bupropion have been prospectively registered (89 pending delivery, 542 cases lost to follow-up, and 944 cases with 955 outcomes were obtained (includes 9 sets of twins and 1 triplet set). The outcomes reported to date represent an insufficient sample size to draw conclusions especially given the large number of cases lost to follow-up. However, because previous reports from this registry suggested a potential increased risk of birth defects involving the heart and great vessels, a claims-based, retrospective cohort study was conducted. The results of this study suggest that there is not an increased risk of overall congenital malformations, or cardiac malformations in either the first trimester or throughout pregnancy compared with reference groups of pregnant women taking other antidepressants (Cole et al., 2007). Due to the insufficient data available on human prenatal exposures to bupropion, and because animal reproduction studies are not always predictive of human response, it is difficult to compare the risks vs. benefits of bupropion in pregnant smokers.

Varenicline is FDA pregnancy category C. There are currently no data on the outcomes of pregnancies in which mothers have used of varenicline for smoking cessation. In reproductive and developmental toxicity studies, pregnant rats and rabbits received varenicline succinate during organogenesis at oral doses up to 15 and 30 mg/kg/day, respectively. These exposures were 36 (rats) and 50 (rabbits) times the human exposure at the maximum recommended human dose (MRHD) of 1 mg BID. While no fetal structural abnormalities occurred in either species, reduced fetal weights occurred in rabbits at the highest dose (exposures 50 times the human exposure at the MRHD based on AUC). Fetal weight reduction did not occur at animal exposures 23 times the human exposure at the MRHD based on AUC.

In a pre- and postnatal development study, pregnant rats received up to 15 mg/kg/day of oral varenicline succinate from organogenesis through lactation. These resulted in exposures up to 36 times the human exposure at the MRHD of 1 mg BID. Decreased fertility and increased auditory startle response occurred in offspring.



Benowitz N, Dempsey D. Pharmacotherapy for smoking cessation during pregnancy. Nicotine Tob Res. 2004; 6 Suppl 2: S189-S202.

Cole JA, Modell JG, Haight BR, Cosmatos IS, Stoler JM, Walker AM. Bupropion in pregnancy and the prevalence of congenital malformations. Pharmacoepidemiol Drug Saf. 2007; 16: 474-484.

Rigotti NA, Park ER, Chang Y, Regan S. Smoking cessation medication use among pregnant and postpartum smokers. Obstet Gynecol. 2008; 111: 348-355.

Coleman T. Recommendations for the use of pharmacological smoking cessation strategies in pregnant women. CNS Drugs. 2007; 21: 983-993.

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