This study was completed at Colorado State University, Fort Collins, Colorado.
The Pharmacokinetics of Mirtazapine in Cats with Chronic Kidney Disease and In Age-Matched Control Cats
Version of Record online: 30 AUG 2011
Copyright © 2011 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 25, Issue 5, pages 985–989, September/October 2011
How to Cite
Quimby, J.M., Gustafson, D.L. and Lunn, K.F. (2011), The Pharmacokinetics of Mirtazapine in Cats with Chronic Kidney Disease and In Age-Matched Control Cats. Journal of Veterinary Internal Medicine, 25: 985–989. doi: 10.1111/j.1939-1676.2011.00780.x
This study was funded by a grant from the Winn Feline Foundation.
Presented in part as an abstract at the 2010 ACVIM Forum, Anaheim, CA.
- Issue online: 20 SEP 2011
- Version of Record online: 30 AUG 2011
- Manuscript Accepted: 6 JUL 2011
- Manuscript Revised: 27 MAY 2011
- Manuscript Received: 2 FEB 2011
Cats with chronic kidney disease (CKD) often experience inappetence, and may benefit from administration of mirtazapine, an appetite stimulant. The pharmacokinetics of mirtazapine in CKD cats is unknown.
CKD delays the clearance/bioavailability (CL/F) of mirtazapine.
Six CKD cats and 6 age-matched controls (AMC) were enrolled. Two CKD cats each from International Renal Interest Society (IRIS) stage II, III and IV were included.
Blood samples were collected before and 0.5, 1, 1.5, 2, 4, 8, 24, and 48 hours after a single PO dose of 1.88 mg of mirtazapine. Mirtazapine concentrations were measured by liquid chromatography coupled to tandem mass spectrometry. Non-compartmental pharmacokinetic modeling was performed.
Mean age was 11 years (CKD cats) and 10.8 years (AMC cats). Mean serum creatinine concentration ± standard deviation (SD) was 3.8 ± 1.6 mg/dL (CKD) and 1.3 ± 0.4 mg/dL (AMC). Mean half-life ± SD was 15.2 ± 4.2 hours (CKD) and 12.1 ± 1.1 hours (AMC). Mean area under the curve (AUC) ± SD was 770.6 ± 225.5 ng/mL•hr (CKD) and 555.5 ± 175.4 ng/mL•hr (AMC). Mean CL/F ± SD was 0.6 ± 0.1 L/hr/kg (CKD) and 0.8 ± 0.16 L/hr/kg (AMC). A Mann-Whitney test indicated statistically significant differences in AUC (P = 0.01) and CL/F (P = 0.04) between groups. Calculated accumulation factor for 48-hour dosing in CKD cats was 1.15.
CKD may delay the CL/F of mirtazapine. A single low dose of mirtazapine resulted in a half-life compatible with a 48-hour dosing interval in CKD cats.