Abstrakt
Guaifenesin is used as an expectorant and it has been reported to possess muscle relaxant and sedative activity. Guaifenesin has been used as a component of composite OTC analgesics containing paracetamol for many years.
The aim of our study was to ascertain effects of guaifenesin on paracetamol analgesic activity and locomotor performance. Antinociceptive efficacy was tested in mice using an acetic acid (0.7%) writhing test.
Locomotor performance was tested in rota-rod test and activity cage. All drugs were given orally and tested in mice.
In combination with a subeffective dose of guaifenesin (200 mg/kg), the ED50 for paracetamol in the writhing test was significantly lower (82.2 mg/kg) than that of paracetamol administered alone (233.7 mg/kg). Guaifenesin alone did not show an analgesic effect.
Guaifenesin did not produce statistically significant locomotor impairment in the rota-rod test at doses enhancing analgesic activity of paracetamol, although there was a trend for decreased locomotor activity in activity cage. The present results indicate that guaifenesin may enhance analgesic activity of paracetamol