Exemestane

The Basics

What is Exemestane?

Used to treat early breast cancer in postmenopausal women who have already been treated with a medication called tamoxifen (Nolvadex) for 2 to 3 years.

Brand names for Exemestane

Aromasin

How Exemestane is classified

Antineoplastic Agents, Aromatase Inhibitors

Exemestane During Pregnancy

Exemestane pregnancy category

Category Not AssignedNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Exemestane while pregnant

Based on findings in animal studies and its mechanism of action, AROMASIN can cause fetal harm when administered to a pregnant woman [see CLINICAL PHARMACOLOGY]. Limited human data from case reports are insufficient to inform a drug-associated risk. In animal reproduction studies, administration of exemestane to pregnant rats and rabbits caused increased incidence of abortions, embryo-fetal toxicity, and prolonged gestation with abnormal or difficult labor . Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Data Animal Data In animal reproduction studies in rats and rabbits, exemestane caused embryo-fetal toxicity, and was abortifacient. Radioactivity related to 14C-exemestane crossed the placenta of rats following oral administration of 1 mg/kg exemestane. The concentration of exemestane and its metabolites was approximately equivalent in maternal and fetal blood. When rats were administered exemestane from 14 days prior to mating until either days 15 or 20 of gestation, and resuming for the 21 days of lactation, an increase in placental weight was seen at 4 mg/kg/day (approximately 1.5 times the recommended human daily dose on a mg/m² basis). Increased resorptions, reduced number of live fetuses, decreased fetal weight, retarded ossification, prolonged gestation and abnormal or difficult labor was observed at doses equal to or greater than 20 mg/kg/day (approximately 7.5 times the recommended human daily dose on a mg/m² basis). Daily doses of exemestane, given to rabbits during organogenesis, caused a decrease in placental weight at 90 mg/kg/day (approximately 70 times the recommended human daily dose on a mg/m² basis) and in the presence of maternal toxicity, abortions, an increase in resorptions, and a reduction in fetal body weight were seen at 270 mg/kg/day. No malformations were noted when exemestane was administered to pregnant rats or rabbits during the organogenesis period at doses up to 810 and 270 mg/kg/day, respectively (approximately 320 and 210 times the recommended human dose on a mg/m² basis, respectively).

Taking Exemestane While Breastfeeding

What are recommendations for lactation if you're taking Exemestane?

No information is available on the use of exemestane during breastfeeding. Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy. The manufacturer recommends that breastfeeding be discontinued during exemestane therapy and for 1 month after the last dose.

Maternal / infant drug levels

No information is available on the use of exemestane during breastfeeding. Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy. The manufacturer recommends that breastfeeding be discontinued during exemestane therapy and for 1 month after the last dose.

Possible effects of Exemestane on milk supply

Relevant published information was not found as of the revision date.

Possible alternatives to Exemestane

None listed