title: Disposition of penicillin G sodium following intravenous and oral administration to Equidae.
abstract: The present study was designed to determine and compare the plasma disposition and pharmacokinetics of penicillin G sodium following intravenous (i.v.) administration to horses, ponies and donkeys. The plasma disposition and pharmacokinetics of penicillin G was similar in horses, ponies and donkeys (elimination half-lives--39.0, 27.3 and 31.5 min, respectively) and a dosage interval of 6-8 h would be suitable to treat infections caused by susceptible bacteria. Although penicillin G was absorbed rapidly following nasogastric administration, the systemic availability was low (0.12-0.34%), therefore oral administration would be unsuitable for systemic antimicrobial therapy in the equine. The elimination of penicillin G into the gastrointestinal tract following i.v. administration and the absorption of penicillin G from the gastrointestinal tract following oral administration were studied in two ponies with cannulated caecal fistulas. A low concentration of penicillin G (< or = 0.6 micrograms ml-1) was measured in caecal liquor following i.v. administration, however the risk of development of antimicrobial-associated colitis would be high following oral administration of penicillin G since high concentrations of drug (4.96-157.12 micrograms ml-1) were measured in caecal liquor.
authors.affiliation: Department of Veterinary Pharmacology, University of Glasgow Veterinary School, Scotland.
authors.forename: L J
authors.initials: LJ
authors.lastname: Horspool
authors.forename: Q A
authors.initials: QA
authors.lastname: McKellar
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002432:Cecum / Q000378:metabolism; D018397:Equidae / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D005260:Female; D007275:Injections, Intravenous / Q000662:veterinary; D007408:Intestinal Absorption; D008297:Male; D010400:Penicillin G / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010406:Penicillins / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D010406:Penicillins; D010400:Penicillin G