Role of community pharmacies for the detection of potentially inappropriate xanthine oxidase inhibitor prescriptions

Background Xanthine oxidase (XO) inhibitors are largely the treatment of choice for gout, but allopurinol is often inappropriately used for asymptomatic hyperuricemia. There is little evidence that allopurinol is useful in preventing cardiovascular diseases and therapeutic decisions must the balance the expected benefit with the potential harm. Objective To investigate the appropriateness of XO inhibitor use in relation to evidence-based indications and examine the role of community pharmacies in the detection of inappropriate prescriptions of these drugs. Methods This is an observational study conducted in eight community pharmacies. Each pharmacist was asked to interview a sample of patients who had received prescriptions of XO inhibitors. Patients were asked to complete a structured minimum data set that collected information on drug indication, history of gout, and presence of cardiovascular diseases. Results The study sample included 74 patients receiving XO inhibitors. About one third of patients reported being treated for asymptomatic hyperuricemia and had never had a gout attack. About half of the patients treated for asymptomatic hyperuricemia had been receiving the drug treatment for more than 3 years. Four asymptomatic hyperuricemic patients received allopurinol to treat hypertension. Among the patients treated for asymptomatic hyperuricemia, there was a higher presence of diabetes mellitus, obesity, previous myocardial infarction, and heart failure than in patients treated for an appropriate indication. Conclusions Inappropriate use of XO inhibitors is principally related to the treatment of hyperuricemia in patients with cardiovascular diseases. Community pharmacists have a central role in pharmacovigilance, by contributing to the prevention and identification of potentially inappropriate drug prescriptions.