Warfarin in the dog: pharmacokinetics as related to clinical response.
Warfarin was administered intravenously (i.v.) as a single dose of 1.5 mg/kg to healthy dogs and the pharmacokinetic parameters were investigated. Elimination could be described by a one-compartment open model. Values for the elimination half-life and apparent specific volume of distribution were 14.5 +/- 4.1 h and 0.22 +/- 0.04 litre/kg, respectively. Oral maintenance doses were calculated from the data collected following i.v. administration and administered every 12 h for a total of five doses after an initial i.v. loading dose of 1.5 mg/kg. Prothrombin times increased from a control value of 8.6 +/- 0.3 sec to 55.2 +/- 5.2 sec over a period of 96 h. Prothrombin time returned to control values by 62 h after withdrawal of the drug. We propose a dosage regimen of warfarin for anticoagulant therapy in the dog of 0.22 mg/kg to be given orally every 12 h. Prothrombin time should be monitored during therapy and the dose of warfarin modified according to the degree of suppression of coagulation factors desired.
D000284:Administration, Oral; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D004285:Dogs / Q000378:metabolism*; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D011485:Protein Binding; D011517:Prothrombin Time / Q000662:veterinary; D014859:Warfarin / Q000097:blood / Q000378:metabolism*
D001798:Blood Proteins; D014859:Warfarin