Carroll G L, Hooper R N, Boothe D M, Hartsfield S M, Randoll L A
Department of Small Animal Medicine, College of Veterinary Medicine, Texas A&M University, College Station 77843-4461, USA.
Am J Vet Res. 1999 Aug;60(8):986-91.
To evaluate disposition of fentanyl in goats after IV and transdermal administration.
8 healthy 2-year-old goats weighing 31.8 to 53.6 kg (mean+/-SD, 40.4+/-7.5 kg).
Each goat was given 2 treatments consisting of fentanyl administered IV (2.5 microg/kg of body weight) and via a transdermal patch (50 microg/h). There was a 2-month interval between treatments. Blood samples were collected at specified times and analyzed in duplicate to determine plasma fentanyl concentrations. Pharmacokinetic values were calculated, using a computerized modeling program.
Administration of fentanyl was tolerated by all goats. Intravenous administration of fentanyl resulted in a transitory increase in rectal temperature that was not clinically important. Terminal elimination half-life after IV administration was 1.20+/-0.78 h, volume of distribution at steady state was 1.51+/-0.39 L/kg, and systemic clearance was 2.09+/-0.62 L/kg/h. Transdermal administration of fentanyl resulted in variable plasma concentrations, with peak plasma concentrations ranging from 1.12 to 16.69 ng/ml (mean+/-SD, 6.99+/-6.03 ng/ml) and time to peak concentration ranging from 8 to 18 hours (mean+/-SD, 13+/-4.5 hours). After removal of the transdermal patch, mean+/-SD terminal elimination half-life was 5.34+/-5.34 hours.
Intravenous administration of fentanyl (2.5 microg/kg) in goats results in a relatively short half-life that will limit its use for management of pain. Transdermal administration of fentanyl (50 microg/h) in goats results in variable plasma concentrations that may exceed those anticipated on the basis of a theoretical delivery rate, but stable plasma concentrations of fentanyl may not be achieved.
评估静脉注射和经皮给药后山羊体内芬太尼的处置情况。
8只健康的2岁山羊，体重31.8至53.6千克（平均±标准差，40.4±7.5千克）。
每只山羊接受2种治疗，包括静脉注射芬太尼（2.5微克/千克体重）和经皮贴剂给药（50微克/小时）。两次治疗间隔2个月。在特定时间采集血样并进行双份分析，以测定血浆芬太尼浓度。使用计算机建模程序计算药代动力学值。
所有山羊对芬太尼给药均耐受。静脉注射芬太尼导致直肠温度短暂升高，但在临床上并不重要。静脉注射后的终末消除半衰期为1.20±0.78小时，稳态分布容积为1.51±0.39升/千克，全身清除率为2.09±0.62升/千克/小时。经皮给药芬太尼导致血浆浓度变化，血浆峰浓度范围为1.12至16.69纳克/毫升（平均±标准差，6.99±6.03纳克/毫升），达峰时间范围为8至18小时（平均±标准差，13±4.5小时）。移除经皮贴剂后，平均±标准差的终末消除半衰期为5.34±5.34小时。
山羊静脉注射芬太尼（2.5微克/千克）导致半衰期相对较短，这将限制其在疼痛管理中的应用。山羊经皮给药芬太尼（50微克/小时）导致血浆浓度变化，可能超过基于理论释放速率预期的浓度，但可能无法实现芬太尼血浆浓度稳定。
