Pharmacokinetics of cetirizine in healthy cats

Am J Vet Res. 2008 May;69(5):670-4. doi: 10.2460/ajvr.69.5.670.


Objective: To develop a high-performance liquid chromatography (HPLC) assay for cetirizine in feline plasma and determine the pharmacokinetics of cetirizine in healthy cats after oral administration of a single dose (5 mg) of cetirizine dihydrochloride.

Animals: 9 healthy cats.

Procedures: Heparinized blood samples were collected prior to and 0.5, 1, 2, 4, 6, 8, 10, and 24 hours after oral administration of 5 mg of cetirizine dihydrochloride to each cat (dosage range, 0.6 to 1.4 mg/kg). Plasma was harvested and analyzed by reverse-phase HPLC. Plasma concentrations of cetirizine were analyzed with a compartmental pharmacokinetic model. Protein binding was measured by ultrafiltration with a microcentrifugation system.

Results: No adverse effects were detected after drug administration in the cats. Mean +/- SD terminal half-life was 10.06 +/- 4.05 hours, and mean peak plasma concentration was 3.30 +/- 1.55 microg/mL. Mean volume of distribution and clearance (per fraction absorbed) were 0.24 +/- 0.09 L/kg and 0.30 +/- 0.09 mL/kg/min, respectively. Mean plasma concentrations were approximately 2.0 microg/mL or higher for 10 hours and were maintained at > 0.72 microg/mL for 24 hours. Protein binding was approximately 88%.

Conclusions and clinical relevance: A single dose of cetirizine dihydrochloride (approx 1 mg/kg, which corresponded to approximately 0.87 mg of cetirizine base/kg) was administered orally to cats. It was tolerated well and maintained plasma concentrations higher than those considered effective in humans for 24 hours after dosing. The half-life of cetirizine in cats is compatible with once-daily dosing, and the extent of protein binding is high.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Anti-Allergic Agents / blood
  • Anti-Allergic Agents / pharmacokinetics*
  • Area Under Curve
  • Cats / blood
  • Cats / metabolism*
  • Cetirizine / blood
  • Cetirizine / pharmacokinetics*
  • Chromatography, High Pressure Liquid / methods
  • Chromatography, High Pressure Liquid / veterinary
  • Female
  • Half-Life
  • Male


  • Anti-Allergic Agents
  • Cetirizine