Genetic Test for Carbamazepine-Induced Stevens-Johnson Syndrome Carbamazepine (Tegretol, Carbatrol, Equetro, and others), which is now used to treat not only epilepsy but also trigeminal neuralgia and manic episodes in patients with bipolar disorder,1 is a known cause of Stevens-Johnson syndrome (SJS). The incidence of carbamazepine-induced SJS in countries with mainly white populations is 1 to 6 per 10,000 new users of the drug, but Asian patients have a 10-fold higher incidence of this reaction. An association has been found between the human leukocyte antigen (HLA)-B*1502 allele and carbamazepine-induced SJS in a Chinese population.2 This allele occurs almost exclusively in Asians.3,4 The FDA is now recommending that Asian patients be tested for genetic susceptibility to carbamazepine-induced SJS before starting the drug. The genetic test should be available in most clinical chemistry labs.

1. Extended-release carbamazepine (Equetro) for bipolar disorder. Med Lett Drugs Ther 2005; 47:27.

2. WH Chung et al. Medical genetics: a marker for Stevens- Johnson syndrome. Nature 2004; 428:486.

3. C Lonjou et al. A marker for Stevens-Johnson syndrome. . . : ethnicity matters. Pharmacogenomics J 2006; 6:265.

4. A Alfirevic et al. HLA-B locus in Caucasian patients with carbamazepine hypersensitivity. Pharmacogenomics 2006; 7:813.