Inpatients with Allopurinol Hypersensitivity Syndrome: Experiences at a Medical Center in Southern Taiwan

Abstract

Allopurinol is considered an effective and safe uric-acid lowering drug but occasional severe allopurinol hypersensitivity syndrome (AHS) may develop. Reviewing the records of 22 inpatients with AHS at our hospital, impaired renal function and old age seem to play an important role in the development of AHS. Three cases developed AHS with elevation of total 1gE level only 5-10 minutes after taking 100mg of allopurinol. This finding seems to imply that type I hypersensitivity could play a part in the development of AHS. One patient experienced 5 episodes of AHS due to the ignorance of AHS history at other hospitals or drug stores, which could be avoided by giving these patients Medic-Alert bracelets, noting the history of AHS. Twelve cases (54.5%) received allopurinol because of asymptomatic hyperuricemia, which is a common practice in Southern Taiwan but not an established indication for starting allopurinol. The chances of developing AHS could be lowered if the clinicians follow the proper indications for the use of allopurinol. We suggest that allopurinol should be prescribed in cases that exhibit proper indications. And the dosage for patients with impaired renal function and/or older age should be adjusted.