Effects of tolmetin, paracetamol, and of two combinations of tolmetin and paracetamol as compared to placebo on experimentally induced pain. A double blind study.

Abstract

Previous studies in animals suggested that a coadministration of the anti-rheumatic/anti-inflammatory agent tolmetin (Tolectin) and of paracetamol potentiates the effects of these two drugs. The present study was carried out to assess whether or not the dosis of tolmetin necessary to obtain an analgesic effect can be reduced when paracetamol is coadministered in a model with experimentally induced pain in healthy human subjects. The effects of tolmetin 200 mg (T 200), paracetamol 400 mg (P 400), tolmetin 150 mg plus paracetamol 300 mg (T 150 + P 300), and of tolmetin 100 mg plus paracetamol 400 mg (T 100 + P 400) on pain threshold to electrical and thermal stimuli and on pain tolerance to electrical stimuli were compared to the effects of placebo under double blind conditions. Each of 20 healthy volunteers received all of the 5 treatments randomised according to four 5 X 5 Latin squares. The results showed that the combination T 100 + P 400 had better analgesic effects than the double dose of tolmetin, T 200, alone, while the effects of P 400 could not be discrminated from placebo. In a sequential t-test the effects of T 100 + P 400 could be discriminated from placebo already after 14 Ss. The effects of T 200, T 150 + P 300, and T 100 + P 400 respectively could not be differentiated, indicating that the dose of tolmetin can be reduced markedly by simultaneous administration of paracetamol without a loss in analgesic potency. Coadministration of tolmetin and paracetamol permits a marked reduction of the dose of tolmetin without any loss of analgesic potency as measured in a model with experimentally induced pain in healthy subjects.