Pharmacokinetics of naloxone and naltrexone in the dog.
The serum kinetics of 5 mg/kg of i. v. naloxone or naltrexone were studied in each of two groups of five dogs; serum samples were obtained from 2 min to 2 hr after injection. Serum concentrations were determined by radioimmunoassay. Serum levels of both naloxone and naltrexone fell rapidly; serum half-life during the elimination phase was 71.2 +/- 8.9 min (mean +/- S.E.) for naloxone and 85.1 +/- 9.0 min (mean +/- S.E.) for naltrexone. Although human and dog kinetics are similar for naloxone, naltrexone is long-acting in man, but is quickly dissipated in the dog.
D000818:Animals; D004285:Dogs; D005260:Female; D006207:Half-Life; D007700:Kinetics; D008297:Male; D009270:Naloxone / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism*; D009271:Naltrexone / Q000097:blood / Q000378:metabolism*; D011863:Radioimmunoassay
D009270:Naloxone; D009271:Naltrexone