Investigation of the impact of urine handling procedures on interpretation of urinalysis findings and product safety in subjects treated with ezogabine

Ezogabine (also known by the international nonproprietary name of retigabine) is an antiepileptic drug codeveloped and comarketed by Valeant Pharmaceuticals North America and GlaxoSmithKline, which reduces neuronal excitability by enhancing the activity of potassium channels and has the potential to have effects on the urinary system through a pharmacologic action on bladder smooth muscle. In a single post-herpetic neuralgia trial, but not in an extensive epilepsy development program, proteinuria was unexpectedly reported in patients receiving ezogabine. Consequently, investigations were conducted to determine whether the reported proteinuria represented a true or false-positive finding.