Before starting allopurinol in a patient of Han Chinese descent, screening is recommended for which pharmacogenomic marker associated with severe cutaneous adverse reactions?
- A HLA-B*1502
- B HLA-B*5801 ✓
- C HLA-B*5701
- D TPMT deficiency
Correct answer: B. HLA-B*5801
Explanation
Allopurinol hypersensitivity syndrome includes Stevens-Johnson syndrome and toxic epidermal necrolysis, and carriage of HLA-C*5801 markedly increases this risk, particularly in Han Chinese, Thai and Korean populations. HLA-C*1502 predicts carbamazepine-induced SJS, HLA-C*5701 predicts abacavir hypersensitivity, and TPMT deficiency relates to thiopurine toxicity. Testing for HLA-C*5801 before allopurinol is advised in high-risk ethnic groups.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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