2006, Number 4
Rev Mex Anest 2006; 29 (4)
Pre-clinical analysis (rat) of antinociceptive effects of association between tramadol and acetaminophen
López-Muñoz FJ, Moreno-Rocha LA, Moreno-T J, Domínguez-Ramírez AM, Bravo G
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ABSTRACTCompounds containing two different analgesic agents or one analgesic with other types of drugs are widely used in therapeutics. A lot of these compounds are formulated in order to produce greater analgesic effects or to diminish severe untoward effects. In this respect, several analgesic drug compounds have been employed in the treatment of human pain for many years. However, few well-controlled studies have been performed to determine the relative effectiveness and the possible advantages of such a combination over the single drug therapy. As a matter of fact, the benefits of the above combinations are difficult to be demonstrated in clinical tests. Therefore, the present work has used the «Pain-Induced Functional Impairment Model in Rat» (PIFIR model) to assess the antinociceptive effects of acetaminophen (31.6 to 562.3 mg/kg p.o.), tramadol (17.8 to 56.2 mg/kg p.o.), as well as 6 different combinations of acetaminophen + tramadol. The recovery of functionality after the treatments was considered as an expression of antinociception in rats. This fact allowed us to detect the antinociceptive interaction profile of the combinations. The antinociceptive effects produced by the combinations acetaminophen/tramadol were similar to those ones expected from the sum of antinociceptive effects of the individual drugs. The acetaminophen showed less antinoceptive potency and efficacy than tramadol. The present results indicate that it is important to characterize the potential analgesic activities of combinations containing opioids and NSAIDs because of their possible application in the treatment of similar human pain.