ISOMETHEPTENE

Fetal Risk Summary

The sympathomimetic drug, isometheptene, is commercially available in combination with dichloralphenazone and acetaminophen (e.g., Isocom, Isopap, Midchlor, Midrin, and Migratine) for the treatment of tension and vascular (migraine) headaches (see also Dichloralphenazone and Acetaminophen). No animal reproductive studies of isometheptene have been located.

The Collaborative Perinatal Project, conducted between 1958 and 1965, recorded eight 1st trimester exposures to isometheptene among 96 mothers who had consumed a miscellaneous group of sympathomimetics (1). From these 96 mothers, 7 children had congenital malformations producing a standardized relative risk (SRR) of 0.96. When only malformations showing uniform rates by hospital were analyzed, the number of children with defects decreased to 4 (SRR 0.81). The authors of this study concluded there was no association between these agents and congenital anomalies.

A 1984 source briefly reviewed isometheptene (2). Although citing no primary References, the authors concluded that the agent was not contraindicated in pregnancy because of the lack of reports of harmful effects on the fetus, the mother, and the pregnancy (2).

Breast Feeding Summary

No data are available.

References

1. Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA:Publishing Sciences Group, 1977:346.
2. Onnis A, Grella P. The Biochemical Effects of Drugs in Pregnancy. Volume 1. West Sussex, England:Ellis Horwood Limited, 1984:179.