%0 Journal Article %T Effect of oral co-administration of frozen-dried grapefruit juice on pharmacokinetics of tramadol in dogs %J Iranian Journal of Veterinary Research %I Shiraz University %Z 1728-1997 %A Giorgi, M. %A MacCheroni, M. %A Del Carlo, S. %A Yun, H. I. %A Saccomanni, G. %D 2011 %\ 03/01/2011 %V 12 %N 1 %P 8-15 %! Effect of oral co-administration of frozen-dried grapefruit juice on pharmacokinetics of tramadol in dogs %K Tramadol %K Metabolites %K Frozen-dried grapefruit-juice %K pharmacokinetics %K dog %R 10.22099/ijvr.2011.35 %X Tramadol is a centrally acting analgesic drug extensively metabolized in animal species. Its clinicalresponse is mainly due to the M1 metabolite, poorly produced in dogs. Grapefruit-juice can inhibit themetabolism of different drugs in animals and humans. The aim of the present study was to evaluate thepharmacokinetics of tramadol and its major metabolites after co-administration of tramadol and frozen-dried grapefruit-juice. A balanced cross-over study was used involving six male Beagle dogs. They were administered with tramadol alone (5 mg/kg) or with tramadol (5 mg/kg) plus frozen-dried grapefruit-juice (10 g). The plasma concentration vs time curves showed significant differences during the first 4 h following drug administration. Tmax was at 1.33 and 1.70 h following tramadol and tramadol plus frozen-dried grapefruit-juice treatment, respectively. Significant differences were also shown in Cmax (490 vs 270 ng/ml) and AUC (11,610 vs 5,890 h·h·ng/ml). Significant differences between the treatments were shown in all the M1 parameters reported. M2 and M5 did not show significant differences after both administrations. In conclusion, the frozen-dried grapefruit-juice was shown to affect the plasma concentrations of M1, despite them being well below those reported in humans. %U https://ijvr.shirazu.ac.ir/article_35_d6922aa9084bdd30108c7746def50172.pdf