The U.S. Food and Drug Administration (FDA) beefed-up warnings for carbamazepine, a medication used to treat epilepsy, bipolar disorder, and nerve pain. Included among the changes is a new recommendation that patients of Asian descent undergo genetic testing before using the drug.

Carbamazepine is sold as a generic drug under the brand names Carbatrol (Shire PLC), Tegretol (Novartis AG), and Equetro (Validus Pharmaceuticals Inc.). The drugs already carry a warning in the prescribing information of the possibility of rare but severe, and at-times life-threatening, skin reactions for all patients beginning therapy; the difference is that the FDA has now requested that this warning be moved to a more prominent location in an already-existing black box warning on the drug’s label.

Skin reactions include Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN), allergic reactions that can cause severe blistering, rashes, and fever, and, under certain circumstances, may be fatal.

According to the FDA, research has indicated a relationship between certain serious skin reactions to the drug and an inherited variant of the gene HLA-B 1502, which is almost exclusively found in individuals of Asian descent. The FDA’s genetic testing recommendation for such individuals will also be added to the drugs’ boxed warning.

Source: Jennifer Corbett Dooren, “Epilepsy Drug to Get Stronger Warning,” Wall Street Journal, December 13, 2007.