Stamp LK et al. – Starting allopurinol at a dose of 1.5mg per unit eGFR may be associated with a reduced risk of Allopurinol hypersensitivity syndrome (AHS). In patients who tolerate allopurinol the dose can be gradually increased to achieve the target SU.Methods
- A retrospective case–control study of patients with gout who developed AHS between January 1998 and September 2010 was undertaken.
- For each case, three controls with gout receiving allopurinol who did not develop AHS were identified.
- Controls were matched on gender, diuretic use at the time of commencing allopurinol, age ± 10 years, and eGFR. Analysis compared starting dose and dose at the time of the reaction between cases and controls.
- Fifty–four AHS cases and 157 controls were identified.
- There was an increase in risk of AHS as the starting dose of allopurinol corrected for eGFR increased. For the highest quintile of starting dose≥eGFR, the odds ratio was 23.2 (p<0.01).
- ROC analysis indicated that 91% of AHS cases and 36% of controls started on a dose of allopurinol at ≥1.5mg allopurinol per unit eGFR (mg/ml/min).