Tramadol level in colostrum of bitch receiving intravenous tramadol after cesarean section

Abstract

The effect of intravenous injection of tramadol after cesarean section in ten bitches was study by monitoring anesthetic status until fully recovery. Three milliliters of colostrum were collected at 0, 0.5, 1, 1.5, 2, 3, 4, 5 and 6 hrs after tramadol was given intravenously at dosage 4.4 mg/kg. All colostrum samples were analyzed by reversed phase HPLC with fluorescence detection to measure the tramadol and active metabolite o-desmethytramadol (M1) concentrations. Heart rate, respiratory rate, pulse, blood pressure and saturated oxygen in red blood cell were in normal range during anesthetic time. Complication in bitches and all fetuses was not found. The results showed the highest level of tramadol in colostrum (2,836.10 ng/ml) at 0.5 hr (95%CI: 4,105.80-1,566.30), and continuously decreased from 1 to 3 hr (p > 0.05). Meanwhile, the concentrations of tramadol in colostrum were less than the limit of detection at 4 to 6 hr. The levels of M1 in colostrum was 137.92 ng/ml (95%CI: 183.21-95.90) at 0 hr and significantly increased (p < 0.05) to the highest level at 0.5 hr. (295.55 ng/ml, 95%CI: 442.22-148.90). The colostral M1 concentration was continuously decreased to under the limit of detection at 4 to 6 hr, respectively. From the study, we conclude that breast feeding to puppy should be allowed at least 3 hrs after intravenous tramadol administration.