Retrospective review of allopurinol dose and renal function in gout patients with and without allopurinol reactions

The most common medication used for the treatment of recurrent gouty arthritis or tophaceous gout is allopurinol. It is well known that adverse reactions can occur in patients taking allopurinol. Studies in the 1980s have linked severe allopurinol toxicity to use of standard dose allopurinol in patients with decreased creatinine clearance. Guidelines were proposed that advocated reducing allopurinol dose based on glomerular filtration rate (Hande's guidelines). This may result in under-treatment of gout as the target serum uric acid of 5-6 mg/l may not be achieved. We studied the Veterans' Affairs (VA) hospital patients in Western New York (WNY) to determine the number of patients on allopurinol with hypersensitivity reactions from October 2004 through November 2007. In this case-control study, patients with and without allopurinol reactions identified on the computer database were compared regarding dose of allopurinol and creatinine clearance. Chi-square analysis was used to determine if there was a statistically significant difference between the groups in the number of patients dosed according to Hande's guidelines. Surprisingly, we found that there was a trend towards a higher percentage of cases taking allopurinol dosed appropriately or lower than the recommendations of Hande's guidelines, although the difference was not statistically significant. More patients in the control group were taking ACE inhibitors; otherwise there were no significant differences between the 2 groups in terms of demographic features, concurrent medications, or comorbid conditions. The two groups also did not appear to differ in the degree to which doses varied from the actual recommended doses according to Hande's guidelines.