Lack of efficacy during the switch from brand to generic allopurinol.

We report for the first time the lack of therapeutic effects after the switch from a brand formulation of allopurinol to a generic one. A 56-year-old man, with a 5 years history of well-treated gout arthropathy with allopurinol (Zyloric(®) 300 mg/die), developed acute gout arthropathy after the switch from the brand formulation of allopurinol to a generic one. Clinical evaluation and laboratory findings confirmed the diagnosis of acute gout arthropathy. Generic formulation of the drug was dismissed and Zyloric(®) was administered with an improvement of both clinical symptoms and laboratory findings. In conclusion, even if generic formulations are considered to have the same effects in comparison to the brand one, more data are necessaries in order to well define their effectiveness and rationale use.