title: PHARMACOKINETICS OF TRAMADOL AND O-DESMETHYLTRAMADOL IN LOGGERHEAD SEA TURTLES (CARETTA CARETTA).
abstract: The objective of this study was to determine the pharmacokinetics of two orally administered doses of tramadol (5 and 10 mg/kg) and its major metabolite (O-desmethyltramadol) (M1) in loggerhead sea turtles (Caretta caretta). After oral administration, the half-life of tramadol administered at 5 and 10 mg/kg was 20.35 and 22.67 hr, whereas the half-life of M1 was 10.23 and 11.26 hr, respectively. The maximum concentration (Cmax) for tramadol after oral administration at 5 mg/kg and 10 mg/kg was 373 and 719 ng/ml, whereas that of M1 was 655 and 1,376 ng/ml, respectively. Tramadol administered orally to loggerhead sea turtles at both dosages provided measurable plasma concentrations of tramadol and O-desmethyltramadol for several days with no adverse effects. Plasma concentrations of tramadol and O-desmethyltramadol remained ≥100 ng/ml for at least 48 and 72 hr when tramadol was administered at 10 mg/kg.
authors.forename: Terry M
authors.initials: TM
authors.lastname: Norton
authors.forename: Sherry
authors.initials: S
authors.lastname: Cox
authors.forename: Steven E
authors.initials: SE
authors.lastname: Nelson
authors.forename: Michelle
authors.initials: M
authors.lastname: Kaylor
authors.forename: Rachel
authors.initials: R
authors.lastname: Thomas
authors.forename: Amy
authors.initials: A
authors.lastname: Hupp
authors.forename: Kurt K
authors.initials: KK
authors.lastname: Sladky
mesh_terms: D000701:Analgesics, Opioid / Q000097:blood / Q000493:pharmacokinetics; D000818:Animals; D018592:Cross-Over Studies; D006207:Half-Life; D013223:Statistics as Topic; D014147:Tramadol / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D014426:Turtles / Q000097:blood*
chemical_list: D000701:Analgesics, Opioid; C080580:O-demethyltramadol; D014147:Tramadol
keywords: Analgesia; opioid; pain