Fundamental & clinical pharmacology
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Fundam Clin Pharmacol · Feb 2002
Effects of tramadol on behavioural indicators of colic pain in a rat model of ureteral calculosis.
This study investigated the effect of prolonged administration of tramadol vs. placebo on behavioural indicators of ureteral pain and referred lumbar muscle hyperalgesia in a rat model of artificial ureteral calculosis. Four groups of 10 rats each (female, Sprague-Dawley) were treated twice a day, for 4 days, with i.p. injections of tramadol 1.25 mg/kg, 2.5 mg/kg, 5 mg/kg or saline, respectively. The first injection was delivered 45 min before laparotomy (under pentobarbital anaesthesia) for formation of the stone in the upper left ureter via injection of dental cement. ⋯ Tramadol significantly reduced number and global duration (ANOVA, P < 0.008 and P < 0.004) of ureteral crises with respect to saline and the effect was dose-dependent (linear regression analysis between doses and parameters of crises, P < 0.003 and P < 0.002). The drug also significantly reduced the incidence of referred muscle hyperalgesia (ANOVA, P < 0.0001). It is concluded that tramadol is highly effective in controlling pain phenomena from urinary stones and can represent a valid therapeutic approach in patients with urinary colics.