title: The pharmacokinetics of DPH after the administration of a single intravenous or intramuscular dose in healthy dogs.
abstract: The objective of this study was to determine the pharmacokinetics of diphenhydramine (DPH) in healthy dogs following a single i.v. or i.m. dose. Dogs were randomly allocated in two treatment groups and received DPH at 1 mg/kg, i.v., or 2 mg/kg, i.m. Blood samples were collected serially over 24 h. Plasma concentrations of DPH were determined by high-performance liquid chromatography, and noncompartmental pharmacokinetic analysis was performed with the commercially available software. Cardio-respiratory parameters, rectal temperature and effects on behaviour, such as sedation or excitement, were recorded. Diphenhydramine Clarea , Vdarea and T1/2 were 20.7 ± 2.9 mL/kg/min, 7.6 ± 0.7 L/kg and 4.2 ± 0.5 h for the i.v. route, respectively, and Clarea /F, Vdarea /F and T1/2 20.8 ± 2.7 mL/kg/min, 12.3 ± 1.2 L/kg and 6.8 ± 0.7 h for the i.m. route, respectively. Bioavailability was 88% after i.m. administration. No significant differences were found in physiological parameters between groups or within dogs of the same group, and values remained within normal limits. No adverse effects or changes in mental status were observed after the administration of DPH. Both routes of administration resulted in DPH plasma concentrations which exceeded levels considered therapeutic in humans.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Sanchez
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Valverde
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Sinclair
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Mosley
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: A J
authors.initials: AJ
authors.lastname: Mutsaers
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Hanna
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004155:Diphenhydramine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D004285:Dogs / Q000097:blood / Q000378:metabolism; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male
chemical_list: D006634:Histamine H1 Antagonists; D004155:Diphenhydramine