Risk Summary

There are no adequate and well-controlled studies in pregnant women. Arformoterol tartrate should only be used during pregnancy if the expected benefit to the patient outweighs the potential risk to the fetus. Women should be advised to contact their physician if they become pregnant while taking arformoterol tartrate inhalation solution. In animal reproduction studies with arformoterol administered by the oral route to rats and rabbits at exposures approximately 370 and 8,400 times the adult exposure at the maximum recommended human daily inhalation dose (MRHDID) of 15 mcg every 12 hours, respectively, there were findings of structural abnormalities, embryofetal and infant mortality, and alterations of growth. These adverse effects generally occurred at large multiples of the MRHDID when arformoterol was administered by the oral route to achieve high systemic exposures. No evidence of fetal harm was observed in rabbits at an exposure approximately 4,900 times the MRHDID.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Clinical Considerations

Labor or Delivery:

The potential effect of arformoterol tartrate inhalation solution on labor and delivery is unknown. Because of the potential for beta-agonists interference with uterine contractility, use of arformoterol tartrate inhalation solution during labor should be restricted to whom the benefits clearly outweigh the risk.

Data

Animal Data

In an embryofetal development study in which pregnant rats received doses of 1,000, 5,000 or 10,000 mcg/kg/day from gestation days 6 to 17, arformoterol was shown to be teratogenic based upon findings of omphalocele (umbilical hernia), a malformation, in rat fetuses at exposures approximately 370 times adult exposure at the MRHDID (on an AUC basis with maternal oral doses of 1,000 mcg/kg/day and higher. Maternal toxicity was not observed in rats with exposures up to 2,400 times the MRHDID (on an AUC basis with maternal oral doses up to 10,000 mcg/kg/day). A no-observed-adverse-effect-level (NOAEL) for rat fetuses was not identified. In an embryofetal development study in which pregnant rabbits received doses of 20,000, 40,000 or 80,000 mcg/kg/day from gestation days 7 to 20, arformoterol was shown to be teratogenic based upon findings of malpositioned right kidney, a malformation, in rabbit fetuses at exposures approximately 8400 times and higher than the adult exposure at the MRHDID (on an AUC basis with maternal oral doses of 20,000 mcg/kg/day and higher). Malformations including brachydactyly, bulbous aorta, and liver cysts as well as decreased body weights were observed in rabbit fetuses at doses approximately 26,000 times and higher than the MRHDID in adults (on a mcg/m2 basis with maternal oral doses of 40,000 mcg/kg/day and higher). Malformations including adactyly, lobular dysgenesis of the lung, and interventricular septal defect as well as embryolethality were observed in rabbit fetuses at a dose approximately 52,000 times the MRHDID in adults (on a mcg/m2 basis with a maternal oral dose of 80,000 mcg/kg/day). Maternal toxicity was observed at doses approximately 26,000 times and higher than the MRHDID in adults (on a mcg/m2 basis with maternal oral doses of 40,000 mcg/kg/day and higher). There was no evidence of fetal harm in rabbits at exposures approximately 4,900 times and lower than the adult exposure at the MRHDID (on an AUC basis with maternal oral doses of 10,000 mcg/kg/day and lower). 

In a pre- and post-natal development study, female rats received arformoterol at oral doses of 0, 1,000, 5,000, and 10,000 mcg/kg/day from gestation day 6 through lactation day 20. Lengths of gestation for female rats receiving doses 325 times and higher than the MRHDID (on a mcg/m2basis with maternal oral doses of 1,000 mcg/kg/day and higher) were slightly prolonged, which was attributed to prolonged parturition or dystocia due to the pharmacological action of β-adrenergic agonists such as arformoterol to relax uterine musculature. One female that had received a dose 3,200 times the MRHDID (on a mcg/m2 basis with a maternal oral dose of 10,000 mcg/kg/day) was euthanized due to complications during parturition. Pup survival and body weights were decreased at doses 1,600 times and higher than the MRHDID (on a mcg/m2 basis with maternal oral doses of 5,000 mcg/kg/day and higher) at birth and during lactation. Umbilical hernia, a malformation, was observed for 1 pup at a dose 3,200 times the MRHDID (on a mcg/m2basis with a maternal oral dose of 10,000 mcg/kg/day). Potential developmental delays of rat pups were observed at a dose 3,200 times the MRHDID (on a mcg/m2 basis with a maternal oral dose of 10,000 mcg/kg/day); however, no developmental delays were evident with doses 1,600 times the MRHDID (on a mcg/m2 basis with a maternal oral dose of 5,000 mcg/kg/day).