Pharmacokinetics of ketamine and propofol combination administered as ketofol via continuous infusion in cats
Article first published online: 29 JAN 2012
© 2012 Blackwell Publishing Ltd
Journal of Veterinary Pharmacology and Therapeutics
Volume 35, Issue 6, pages 580–587, December 2012
How to Cite
ZONCA, A., RAVASIO, G., GALLO, M., MONTESISSA, C., CARLI, S., VILLA, R. and CAGNARDI, P. (2012), Pharmacokinetics of ketamine and propofol combination administered as ketofol via continuous infusion in cats. Journal of Veterinary Pharmacology and Therapeutics, 35: 580–587. doi: 10.1111/j.1365-2885.2012.01377.x
- Issue published online: 7 NOV 2012
- Article first published online: 29 JAN 2012
- (Paper received 13 July 2011; accepted for publication 21 December 2011)
Zonca, A., Ravasio, G., Gallo, M., Montesissa, C., Carli, S., Villa, R., Cagnardi, P. Pharmacokinetics of ketamine and propofol combination administered as ketofol via continuous infusion in cats. J. vet. Pharmacol. Therap. 35, 580–587.
The pharmacokinetics of the extemporaneous combination of low doses of ketamine and propofol, known as ‘ketofol’, frequently used for emergency procedures in humans to achieve safe sedation and analgesia was studied in cats. The study was performed to assess propofol, ketamine and norketamine kinetics in six female cats that received ketamine and propofol (1:1 ratio) as a loading dose (2 mg/kg each, IV) followed by a continuous infusion (10 mg/kg/h each, IV, 25 min of length). Blood samples were collected during the infusion period and up to 24 h afterwards. Drug quantification was achieved by HPLC analysis using UV-visible detection for ketamine and fluorimetric detection for propofol. The pharmacokinetic parameters were deduced by a two-compartment bolus plus infusion model for propofol and ketamine and a monocompartmental model for norketamine. Additional data were derived by a noncompartmental analysis. Propofol and ketamine were quantifiable in most animals until 24 and 8 h after the end of infusion, respectively. Propofol showed a long elimination half-life (t1/2λ2 7.55 ± 9.86 h), whereas ketamine was characterized by shorter half-life (t1/2λ2 4 ± 3.4 h) owing to its rapid biotransformation into norketamine. The clinical significance of propofol’s long elimination half-life and low clearance is negligible when the drug is administered as short-term and low-dosage infusion. The concurrent administration of ketamine and propofol in cats did not produce adverse effects although it was not possible to exclude interference in the metabolism.