Canadian pharmacogenomics group recommends genetic testing for patients prescribed carbamazepine

In a recent article published online in the journal Epilepsia, the Canadian Pharmacogenomics Network for Drug Safety (CPNDS) has recommended genetic testing for the alleles HLA-B*15:02 and HLA-A*31:01 in all carbamazepine-naive patients before initiation of treatment. In patients who test positive for either of these alleles, alternative medications should be used.

Carbamazepine is an antiepileptic, and patients with the HLA-B*15:02 and HLA-A*31:01 alleles have been found to be at increased risk for carbamazepine-induced hypersensitivity reactions. These reactions can range from a mild rash to severe and even fatal adverse reactions, such as Stevens-Johnson syndrome or toxic epidermal necrolysis. These hypersensitivity reactions usually occur within the first 3 months of treatment. The authors note that patients with no adverse effects after more than 3 months of carbamazepine treatment do not need to be screened, but that any patients who had a previous hypersensitivity reaction on carbamazepine should have genetic testing.

For more information about the CPNDS recommendation, please read the article:

Recommendations for HLA-B*15:02 and HLA-A*31:01 genetic testing to reduce the risk of carbamazepine-induced hypersensitivity reactions
Amstutz U, Shear NH, Rieder MJ, Hwang S, Fung V, Nakamura H, Connolly MB, Ito S, Carleton BC; the CPNDS clinical recommendation group. Epilepsia 2014 Mar 5. Epub ahead of print. [PMID: 24596466].

>Read more about HLA-B*15:02, HLA-A*31:01 and carbamazepine on PharmGKB

>Read the Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for HLA-B*15:02 and carbamazepine dosing

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