Skeletal Muscle Relaxant
PREGNANCY RECOMMENDATION: Limited Human Data—No Relevant Animal Data
BREASTFEEDING RECOMMENDATION: No Human Data—Probably Compatible
Orphenadrine is an anticholinergic agent used in the treatment of painful skeletal muscle conditions. No published reports of its use in human pregnancy have been located (see also Atropine).
FETAL RISK SUMMARY
An animal study in pregnant rats using large oral doses (15 and 30 mg) produced enlarged bladders containing blood but no other anomalies in 8 of 159 fetuses (1).
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.
No reports describing the use of orphenadrine during human lactation have been located (see also Atropine).
1.Beall JR. A teratogenic study of chlorpromazine, orphenadrine, perphenazine, and LSD-25 in rats. Toxicol Appl Pharmacol 1972;21:230–6. As cited in Shepard TH. Catalog of Teratogenic Agents. 6th ed. Baltimore, MD: The Johns Hopkins University Press, 1989:476–7.