Studies Affecting Your Care

FDA: New pharmacogenetic test improves safety of carbamazepine

The FDA has added pharmacogenetic testing to the safety information included in the product labeling for anti-epileptic medication carbamazepine.

The new labeling information has to do with a rare but very serious and sometimes life-threatening skin condition known as Stevens-Johnson Syndrome that can occur as a side-effect of taking carbamazepine. Carbamazepine is FDA-approved as a treatment for epilepsy, mania/bipolar disorder, and neuropathic pain. Stevens-Johnson Syndrome, or “SJS” has multiple causes including several different medications, viral infections, and cancer. Many cases have no known cause. Read more about SJS here.

The pharmacogenetic test that is now recommended by the FDA concerns a particular version of the HLA-B gene known as HLA-B*1502. This version of the gene is found almost exclusively in people with Asian ancestry. Studies have shown that approximately 1 in 10,000 Caucasian people develop SJS after starting carbamazepine; in contrast, as many as 1 in 20 Asian patients who have the HLA-B*1502 gene will develop SJS after starting carbamazepine. Click here for more information about the specific FDA recommendations for patients and their healthcare providers.

This is the second recent medication label change by the FDA to reflect newly available pharmacogenetic tests. Click here to read about previous examples.