Medications that are folic acid antagonists raise the risk not only of neural tube defects but also of cardiovascular, urinary tract, and orofacial defects, according to Dr. Sonia Hernandez-Diaz of Boston University and her associates.
One group of such agents is dihydrofolate reductase inhibitors, which block the conversion of folate to its more active metabolites. These drugs include aminopterin, sulfasalazine, pyrimethamine, triamterene, trimethoprim, and methotrexate, they reported (N. Engl. J. Med. 343[22]:1608-14, 2000).
A second group of folic acid antagonists acts by affecting other enzymes in folate metabolism, impairing folate absorption, or enhancing folate degradation. These agents include primarily the antiepileptics carbamazepine, phenytoin, primidone, and phenobarbital.
The researchers analyzed data from a birth defect surveillance program and found that maternal use of all of these agents raised by 2-7 times the risks of a variety of cardiovascular anomalies, cleft lip, cleft palate, and urinary tract defects including renal agenesis. The use of vitamin supplements containing folate attenuated these risks in all cases except neonates of mothers using the antiepileptic drugs.
These findings suggest that prenatal vitamins with folate reduce the risk not only of neural tube defects but also of numerous other malformations, the investigators said.
COPYRIGHT 2001 International Medical News Group
COPYRIGHT 2001 Gale Group
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