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HLA-B*1502 pharmacogenomics — GPhC CRA MCQ

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HardCNS TherapeuticsHLA-B*1502 pharmacogenomicsGPhC CRA

A 50-year-old woman is prescribed carbamazepine 200 mg twice daily for trigeminal neuralgia. She is of Han Chinese ancestry. What is the most important pharmacogenomic consideration before starting treatment?

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Correct answer: E — Test for HLA-B*1502 allele before initiating carbamazepine

The HLA-B*1502 allele is strongly associated with carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis, particularly in individuals of Han Chinese, Thai, and other South-East Asian ancestry. The MHRA recommends testing for HLA-B*1502 before starting carbamazepine in patients of these ethnic backgrounds. If positive, carbamazepine (and oxcarbazepine) should be avoided.

Reference: MHRA Drug Safety Update; BNF Carbamazepine