Perez-Reyes M, Wall M E
NIDA Res Monogr. 1981;28:93-101.
3H-naltrexone was administered orally, intravenously, and subcutaneously to groups of normal, male, paid volunteers. The doses given were: 50 mg orally (specific activity 4 microCi/mg), 1 mg intravenously (specific activity 200 microCi/mg), and 5 mg subcutaneously (specific activity 30 microCi/mg). At these doses, the subjects did not experience any noticeable effects. Following intravenous injection, plasma levels of radioactivity were immediately high and declined rapidly during the first 30 minutes and declined gradually thereafter. Following oral or subcutaneous administration, maximal plasma levels were observed to occur one hour after dosing, and reached similar levels to those obtained when the drug was intravenously injected. This finding indicates the excellent bioavailability of naltrexone following oral or subcutaneous administration 3H-naltrexone and/or its metabolites were predominately excreted in the urine, and the renal excretion was similar for all three routes of administration. Fecal excretion is a minor pathway of elimination. The urinary and fecal excretion of 3H-naltrexone was studied in one subject for 133 hours after drug ingestion, and it was found that essentially all of the dose administered was excreted in this period.
对正常男性有偿志愿者分组口服、静脉注射和皮下注射3H-纳曲酮。给药剂量分别为：口服50毫克（比活度4微居里/毫克）、静脉注射1毫克（比活度200微居里/毫克）、皮下注射5毫克（比活度30微居里/毫克）。在这些剂量下，受试者未出现任何明显效应。静脉注射后，血浆放射性水平立即升高，在最初30分钟内迅速下降，此后逐渐下降。口服或皮下给药后，给药1小时后观察到血浆水平达到峰值，且与静脉注射该药时达到的水平相似。这一发现表明口服或皮下给予3H-纳曲酮后纳曲酮具有良好的生物利用度。3H-纳曲酮及其代谢产物主要经尿液排泄，三种给药途径的肾脏排泄情况相似。粪便排泄是次要的消除途径。在一名受试者服药后133小时研究了3H-纳曲酮的尿液和粪便排泄情况，发现在这段时间内基本上所有给药剂量均已排泄。
