Risk Factor: C
Class: Autonomics/ Skeletal muscle relaxants
Fetal Risk Summary
Orphenadrine is an anticholinergic agent used in the treatment of painful skeletal muscle conditions. In a study using pregnant rats, large oral doses (15 and 30 mg) produced enlarged bladders containing blood, but no other anomalies, in 8 of 159 fetuses (1). No published reports of its use in pregnancy have been located (see also Atropine).
In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 411 newborns had been exposed to orphenadrine during the 1st trimester (F. Rosa, personal communication, FDA, 1993). A total of 11 (2.7%) major birth defects were observed (16 expected), including (observed/expected) 2/4 cardiovascular defects and 1/1 polydactyly. No anomalies were observed in four other defect categories (oral clefts, spina bifida, limb reduction defects, and hypospadias) for which specific data were available. These data do not support an association between the drug and congenital defects.
Breast Feeding Summary
No data are available (see also Atropine).
- Beall JR. A teratogenic study of chlorpromazine, orphenadrine, perphenazine, and LSD-25 in rats. Toxicol Appl Pharmacol 1972;21:2306. As cited in Shepard TH. Catalog of Teratogenic Agents. 6th ed. Baltimore, MD: Johns Hopkins University Press, 1989:4767.