Spinosad

8.1 Pregnancy Risk Summary Spinosad, the active ingredient in NATROBA, is not absorbed systemically following topical application, and maternal use is not expected to result in fetal exposure to the drug. NATROBA contains benzyl alcohol. Topical benzyl alcohol is unlikely to be absorbed through the skin in clinically relevant amounts; therefore, maternal use is not expected to result in fetal exposure to the drug [ see Clinical Pharmacology (12.3) ]. In animal reproduction studies, no adverse embryofetal effects were seen at oral doses of spinosad up to 200 mg/kg/day in pregnant rats or 50 mg/kg/day in pregnant rabbits administered during the period of organogenesis ( see Data ).

The available data do not allow the calculation of relevant comparisons between the systemic exposure of spinosad in animal studies to the systemic exposure that would be expected in humans after topical use of NATROBA. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk for birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal Data Systemic embryofetal development studies were conducted in rats and rabbits.

Oral doses of 10, 50 and 200 mg/kg/day spinosad were administered during the period of organogenesis (gestational days 6 – 15) to pregnant female rats. No adverse embryofetal effects were noted at any dose. Maternal toxicity occurred at 200 mg/kg/day. Oral doses of 2.5, 10, and 50 mg/kg/day spinosad were administered during the period of organogenesis (gestational days 7 – 19) to pregnant female rabbits. No adverse embryofetal effects were noted at any dose. Maternal toxicity occurred at 50 mg/kg/day. A two-generation dietary reproduction study was conducted in rats.

Oral doses of 3, 10, and 100 mg/kg/day spinosad were administered to male and female rats from 10-12 weeks prior to mating and throughout mating, parturition, and lactation. No reproductive/developmental toxicity was noted at doses up to 10 mg/kg/day. In the presence of maternal toxicity, increased dystocia in parturition, decreased gestation survival, decreased litter size, decreased pup body weight, and decreased neonatal survival occurred at a dose of 100 mg/kg/day.