BUTALBITAL

Fetal Risk Summary

Butalbital is a short-acting barbiturate that is contained in a number of analgesic mixtures. In a large prospective study, 112 patients were exposed to this drug during the 1st trimester (1). No association with malformations was found. Severe neonatal withdrawal was described in a male infant whose mother took 150 mg of butalbital daily during the last 2 months of pregnancy in the form of a proprietary headache mixture (Esgic-butalbital 50 mg, caffeine 40 mg, and acetaminophen 325 mg/dose) (2). The infant was also exposed to oxycodone, pentazocine, and acetaminophen during the 1st trimester, but apparently these had been discontinued before the start of the butalbital product. Onset of withdrawal occurred within 2 days of birth.

In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 1,124 newborns had been exposed to butalbital during the 1st trimester (F. Rosa, personal communication, FDA, 1993). A total of 53 (4.7%) major birth defects were observed (45 expected). Specific data were available for six defect categories, including (observed/expected) 10/11 cardiovascular defects, 1/2 oral clefts, 0/0.5 spina bifida, 1/3 polydactyly, 2/2 limb reduction defects, and 2/3 hypospadias. These data do not support an association between the drug and congenital defects.

[*Risk Factor D if used for prolonged periods or in high doses at term.]

Breast Feeding Summary

No data are available (see also Pentobarbital).

References

1. Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA:Publishing Sciences Group, 1977:336–7.
2. Ostrea EM. Neonatal withdrawal from intrauterine exposure to butalbital. Am J Obstet Gynecol 1982;143:597–9.