Flupirtine maleate (referred to throughout this paper as flupirtine) capsules 100 mg and suppositories 150 mg were found to be safe and efficacious in several randomized, controlled, double-blind parallel group clinical trials. 586 patients (40 children) suffering from post-operative pain were treated. Flupirtine was significantly more effective than placebo and as well tolerated. It was as effective and acceptable as pentazocine and dihydrocodeine for the treatment of post-operative pain, but offered advantages in terms of fewer central nervous system side effects. It was at least as effective as the non-narcotics metamizole, paracetamol and naproxen.