Efficacy and tolerance of flupirtine and pentazocine in two multicentre trials.

Flupirtine, a non-opioid central analgesic of a new chemical class, was compared to pentazocine in multicentre trials enrolling a total of 1174 patients with pain due to various causes. Treatment was given, depending on the indication, for between 3 days and 8 weeks. For both drugs rectal as well as oral medication was used. Flupirtine proved to be at least as efficacious as pentazocine and was better tolerated producing about half as many adverse reactions and about one third of the drop out rate.