Risk Summary

Available data from published literature and postmarketing experience with use of atovaquone and proguanil hydrochloride in pregnant women are insufficient to identify a drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes . The proguanil component of atovaquone and proguanil hydrochloride tablets acts to inhibit parasitic dihydrofolate reductase; however, pregnant women and females of reproductive potential should continue folate supplementation to prevent neural tube defects [see Clinical Pharmacology ( 12.4)] . Pregnant women with malaria are at increased risk for adverse pregnancy outcomes (see Clinical Considerations).

Atovaquone administered by oral gavage to pregnant rats and rabbits during the period of organogenesis was not associated with fetal malformations at plasma exposures approximately 7 times and equal to, respectively, the estimated human exposure for the treatment of malaria based on AUC. Proguanil administered to pregnant rats and rabbits during the period of organogenesis was not associated with embryo-fetal toxicity at maternally toxic plasma exposures approximately 0.07 and 0.8 times, respectively, the estimated human exposure for treatment of malaria based on AUC (see Data). 

The combination of atovaquone and proguanil hydrochloride given orally by gavage during the period of organogenesis was not associated with embryo-fetal developmental effects in pregnant rats or rabbits at atovaquone:proguanil hydrochloride doses of 50:20 mg/kg/day and 100:40 mg/kg/day, respectively (1.7 and 0.1 times and 0.3 and 0.5 times, respectively, the estimated human exposure for treatment of malaria). In a pre- and post-natal study with atovaquone and another pre-and post-natal study with proguanil, neither compound impaired the growth, development, or reproductive ability of first generation offspring at maternal AUC exposures of approximately 7.3 and 0.04 times, respectively, the estimated human AUC exposure for treatment of malaria (see Data). 

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical Considerations

Disease-Associated Maternal and/or Embryo/Fetal Risk: Malaria during pregnancy increases the risk for adverse pregnancy outcomes, including maternal anemia, prematurity, spontaneous abortion, and stillbirth. 

Data

Animal Data: Atovaquone: Atovaquone administered in oral doses of 250, 500, and 1,000 mg/kg/day during organogenesis (Gestation Day [GD] 6 to GD15) in pregnant rats did not cause maternal or embryo-fetal toxicity at doses up to 1,000 mg/kg/day corresponding to maternal plasma exposures up to 7.3 times the estimated human exposure for the treatment of malaria based on AUC. In pregnant rabbits, atovaquone administered in oral doses of 300, 600, and 1,200 mg/kg/day by gavage during organogenesis (GD6 to GD18) was associated with decreased fetal body length at a maternally toxic dose of 1,200 mg/kg/day corresponding to plasma exposures that were approximately 1.3 times the estimated human exposure during treatment of malaria based on AUC. In a pre- and post-natal study in rats, atovaquone administered in oral doses of 250, 500, and 1,000 mg/kg/day from GD15 until Lactation Day (LD) 20 did not impair the growth or developmental effects in first generation offspring at doses up to 1,000 mg/kg/day corresponding to AUC exposures of approximately 7.3 times the estimated human exposure during treatment of malaria. Atovaquone crossed the placenta and was present in fetal rat and rabbit tissue. 

Proguanil: Proguanil administered orally to pregnant rats during organogenesis (GD6 to GD17) was not associated with fetal malformations, but increased ureter variations at a maternally toxic dose of 20 mg/kg/day corresponding to a plasma concentration approximately equal to 0.07 times the estimated human exposure for the treatment of malaria based on AUC. Proguanil given orally by gavage at a maternally toxic dose of 40 mg/kg/day to pregnant rabbits during organogenesis (GD6 to GD20) did not produce adverse embryo-fetal effects at a plasma concentration up to 0.8 times the estimated human exposure for the treatment of malaria based on AUC. In a pre- and post-natal study in female rats, proguanil hydrochloride administered in oral doses of 4, 8, or 16 mg/kg/day from GD6 until LD20 did not impair the growth, development, or reproductive ability of first generation offspring or the survivability of second generation offspring at doses up to 16 mg/kg/day (0.04 times the average human exposure based on AUC). Pre- and post-natal studies of proguanil in animals at exposures similar to or greater than those observed in humans have not been conducted. 

Atovaquone and Proguanil: The combination of atovaquone and proguanil hydrochloride administered orally to pregnant rats in atovaquone:proguanil hydrochloride doses of 12.5:5, 25:10, and 50:20 mg/kg/day during organogenesis (GD6 to GD17) did not produce maternal toxicity or adverse embryo-fetal developmental effects with doses up to 50:20 mg/kg/day corresponding to plasma concentrations up to 1.7 and 0.1 times, respectively, the estimated human exposure during treatment of malaria based on AUC. In pregnant rabbits, the combination of atovaquone and proguanil hydrochloride administered orally in atovaquone:proguanil hydrochloride doses of 25:10, 50:20, or 100:40 mg/kg/day during organogenesis (GD6 to GD20) did not produce adverse embryo-fetal developmental effects at a maternally toxic dose of 100:40 mg/kg/day corresponding to plasma concentrations of approximately 0.3 and 0.5 times, respectively, the estimated human exposure during treatment of malaria based on AUC.