Advertisement

Antiplatelet effects and pharmacodynamics of clopidogrel in cats

Daniel F. HoganDepartment of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Daniel F. Hogan in
Current site
Google Scholar
PubMed
Close
 DVM, DACVIM
,
Dina A. AndrewsDepartment of Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
Present address is Antech Diagnostics, Irvine, CA.

Search for other papers by Dina A. Andrews in
Current site
Google Scholar
PubMed
Close
 DVM, PhD, DACVP
,
Henry W. GreenDepartment of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Henry W. Green in
Current site
Google Scholar
PubMed
Close
 DVM, DACVIM
,
Kristen K. TalbottDepartment of Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Kristen K. Talbott in
Current site
Google Scholar
PubMed
Close
 BS
,
Michael P. WardDepartment of Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Michael P. Ward in
Current site
Google Scholar
PubMed
Close
 BVSc, MPVM, PhD
, and
Betsy M. CallowayVeterinary Teaching Hospital, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Betsy M. Calloway in
Current site
Google Scholar
PubMed
Close
 BS

Abstract

Objective—To evaluate antiplatelet effects and pharmacodynamics of clopidogrel in cats.

Design—Original study.

Animals—5 purpose-bred domestic cats.

Procedure—Clopidogrel was administered at dosages of 75 mg, PO, every 24 hours for 10 days; 37.5 mg, PO, every 24 hours for 10 days; and 18.75 mg, PO, every 24 hours for 7 days. In all cats, treatments were administered in this order, with at least 2 weeks between treatments. Platelet aggregation in response to ADP and collagen and oral mucosal bleeding times (OMBTs) were measured before and 3, 7, and 10 days (75 and 37.5 mg) or 7 days (18.75 mg) after initiation of drug administration. Serotonin concentration in plasma following stimulation of platelets with ADP or collagen was measured before and on the last day of drug administration. Platelet aggregation, OMBT, and serotonin concentration were evaluated at various times after drug administration was discontinued to determine when drug effects were lost.

Results—For all 3 dosages, platelet aggregation in response to ADP, platelet aggregation in response to collagen, and serotonin concentration were significantly reduced and OMBT was significantly increased at all measurement times during drug administration periods. All values returned to baseline values by 7 days after drug administration was discontinued. No significant differences were identified between doses. None of the cats developed adverse effects associated with drug administration.

Conclusions and Clinical Relevance—Results suggest that administration of clopidogrel at dosages ranging from 18.75 to 75 mg, PO, every 24 hours, results in significant antiplatelet effects in cats. (J Am Vet Med Assoc 2004;225:1406–1411)

Abstract

Objective—To evaluate antiplatelet effects and pharmacodynamics of clopidogrel in cats.

Design—Original study.

Animals—5 purpose-bred domestic cats.

Procedure—Clopidogrel was administered at dosages of 75 mg, PO, every 24 hours for 10 days; 37.5 mg, PO, every 24 hours for 10 days; and 18.75 mg, PO, every 24 hours for 7 days. In all cats, treatments were administered in this order, with at least 2 weeks between treatments. Platelet aggregation in response to ADP and collagen and oral mucosal bleeding times (OMBTs) were measured before and 3, 7, and 10 days (75 and 37.5 mg) or 7 days (18.75 mg) after initiation of drug administration. Serotonin concentration in plasma following stimulation of platelets with ADP or collagen was measured before and on the last day of drug administration. Platelet aggregation, OMBT, and serotonin concentration were evaluated at various times after drug administration was discontinued to determine when drug effects were lost.

Results—For all 3 dosages, platelet aggregation in response to ADP, platelet aggregation in response to collagen, and serotonin concentration were significantly reduced and OMBT was significantly increased at all measurement times during drug administration periods. All values returned to baseline values by 7 days after drug administration was discontinued. No significant differences were identified between doses. None of the cats developed adverse effects associated with drug administration.

Conclusions and Clinical Relevance—Results suggest that administration of clopidogrel at dosages ranging from 18.75 to 75 mg, PO, every 24 hours, results in significant antiplatelet effects in cats. (J Am Vet Med Assoc 2004;225:1406–1411)