Rheumatology

Question 1

Allopurinol most significant adverse effect

Answer 1

The biggest risk the drug poses is DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome, a rare reaction that usually occurs in the presence of chronic kidney disease and diuretic use and has a high mortality rate (see MKSAP 18 Dermatology). A recently discovered DRESS risk factor is the HLA-B5801 allele, which is more common in persons of Han Chinese, Thai, and Korean descent. Screening for HLA-B5801 in high-risk populations is recommended before initiating therapy.