THE ANTI-INFLAMMATORY, ANALGESIC AND ANTI-PYRETIC ACTIVITIES OF NON-NARCOTIC ANALGESIC DRUG MIXTURES IN RATS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 251  (2) , 237-254
Abstract
The effects of nonnarcotic analgesics were examined, separately and in admixture, on carrageenan-induced hind paw edema and on yeast-induced hyperalgesia and hyperthermia in adult rats. The efficacy of the drugs was evaluated using the kinetics of drug-receptor interaction. The hypothesis was tested that the antiinflammatory, analgesic and antipyretic activities of the drug mixtures used equal the addition of the activities of the individual drugs and could be predicted from their intrinsic activities and affinities. Dose-dependent inhibition of paw edema, hyperalgesia and hyperthermia was observed after oral administration of acetylsalicyclic acid (aspirin), paracetamol, phenacetin (60, 125, 250 and 500 mg/kg) and caffeine (12.5, 25, 50 and 100 mg/kg). Over the dose-ranges used, the antiinflammatory activities of paracetamol, phenacetin and caffeine tended to be smaller than that of aspirin. The dose producing a semimaximal effect for caffeine was lower than that for aspirin which in turn was comparable to that for paracetamol or phenacetin. The analgesic activities of phenacetin and caffeine were classified as stronger than that of aspirin, but the efficacy of paracetamol was similar. Paracetamol and aspirin were comparable as antipyretics. The antipyretic activity of phenacetin was higher but that of caffeine was lower thn that of aspirin. For caffeine the dose producing a semimaximal effect was lower than that of aspirin. Within the dose-ranges used, low doses of mixtures of aspirin with either paracetamol, phenacetin or caffeine exhibited antiinflammatory, analgesic and antipyretic activities which were not different from the activities expected on the basis of addition. Incidentally, at some of the higher dose levels potentiation of the activity of the drugs was found. Low doses of the triple combinations: aspirin + paracetamol + caffeine and aspirin + phenacetin + caffeine showed antiinflammatory and antipyretic activities which were not different from those expected on the basis of addition, but the activities observed with higher doses of these combinations indicated potentiation. In the rat, the antiinflammatory, analgesic and antipyretic activities of dual and triple combinations of aspirin, paracetamol, phenacetin and caffeine at least equal the activities expected on the basis of addition.

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