Labels for valproate sodium and related drugs for epilepsy will carry new language warning that children exposed to these agents during gestation may suffer cognitive deficits, the FDA said.
The new information will join existing warnings, added in 2009, that these drugs can cause physical birth defects in their offspring when taken by pregnant women.
Besides valproate sodium (Depacon), drugs affected by the FDA action include divalproex sodium (Depakote, Depakote CP, and Depakote ER) and valproic acid (Depakene and Stavzor). In addition to the seizure-control indication, these agents are also approved to treat manic and mixed episodes related to bipolar disorder and to prevent migraines.
According to the FDA, the warning on cognitive deficits is warranted by "epidemiologic studies that show that children born to mothers who took valproate sodium or related products throughout their pregnancy tend to score lower on cognitive tests (IQ and other tests) than children born to mothers who took other anti-seizure medications during pregnancy."
The primary study, published in 2009 in the New England Journal of Medicine, found mean Differential Ability Scale (DAS) scores of 92 in 3-year-olds born to women taking valproate drugs (95% CI 88 to 97).
In contrast, mean scores in children born to mothers with epilepsy who took other drugs as monotherapy were higher:
- Lamotrigine: 101 (95% CI 98 to 104)
- Carbamazepine: 98 (95% CI 95 to 102)
- Phenytoin: 99 (95% CI 94 to 104)
Other analyses have suggested lower IQ scores and other indicators of cognitive function when children were between the ages of 5 and 16.
The agency noted that the relationship between duration or timing of exposure during pregnancy and the cognitive deficits remains unclear.
Physicians may continue to prescribe valproate drugs as before, and pregnant women currently taking them should not stop abruptly, the FDA said. It also noted that uncontrolled epilepsy and bipolar disorder also carry risks to pregnant women and their offspring.
However, the agency urged that the "benefits and risks [of valproate drugs] should be carefully weighed when prescribing these drugs to women of childbearing age, particularly for conditions not usually associated with permanent injury or death."
The FDA recommended that physicians consider other drugs instead, and if valproate products are prescribed, women of childbearing age should use effective contraception.
The agency also noted that there is a , which is intended to track outcomes of their infants, and it encouraged women eligible to participate to sign up.