DRESS risk factors with allopurinol

• A. Excessive allopurinol dose
• B. Renal dysfunction
• C. All of the above
• D. HTN

Answer: (C)

DRESS with allopurinol is more likely when drug exposure is high or when drug clearance is reduced. Allopurinol and its active metabolite oxypurinol are eliminated by the kidneys, so renal dysfunction leads to accumulation of the drug and increases the risk of a hypersensitivity reaction. A dose that is too high or started too aggressively raises systemic exposure, which similarly elevates the risk. Hypertension isn’t a classic standalone risk factor for allopurinol-induced DRESS, but it often coexists with renal disease or necessitates diuretic therapy, which can influence overall risk. Taken together, these factors explain why all of the above best captures the risk profile.