Effects of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs.
OBJECTIVE
To determine effects of therapeutic dosages of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs.


METHODS
10 hound-crossbred dogs.


METHODS
Aspirin (10 mg/kg, PO, q 12 h), carprofen (4.4 mg/kg, PO, q 24 h), deracoxib (2 mg/kg, PO, q 24 h), meloxicam (0.1 mg/kg, PO, q 24 h), and a placebo were administered for 7 days in a random order to each of 10 healthy dogs; there was a 21-day washout period between subsequent treatments. One-stage prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, and plasma concentrations of thromboxane (TX)B(2) and 6-keto prostaglandin (PG)F(1alpha) were measured before and after treatment administration. Platelet function was assessed by use of a platelet-function analyzer and aggregation.


RESULTS
Aspirin, carprofen, and meloxicam did not significantly affect platelet function. Deracoxib caused a mild decrease in platelet aggregation induced by 50microM ADP. Platelet number, Hct, PT, aPTT, and plasma TXB(2) and 6-keto PGF(1alpha) concentrations were unchanged after NSAID administration. Meloxicam administration resulted in a significant decrease in fibrinogen concentration, but results remained within the laboratory reference interval.


CONCLUSIONS
Oral administration of commonly used NSAIDs at therapeutic dosages in healthy dogs did not alter plasma TXB(2) and 6-keto PGF(1alpha) concentrations. Deracoxib administration resulted in a minor abnormality in platelet aggregation. Anti-inflammatory doses of aspirin did not affect platelet function as measured by use of optical aggregometry and a platelet-function analyzer. Further evaluation of the effects of aspirin and cyclooxygenase-2-selective inhibitors on hemostasis should be performed.
Blois
Shauna L
SL
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada. sblois@uoguelph.ca
Allen
Dana G
DG
Wood
R Darren
RD
Conlon
Peter D
PD
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002227:Carbazoles / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D008297:Male; D000077239:Meloxicam; D010052:Ovariectomy; D010974:Platelet Aggregation / Q000187:drug effects; D011453:Prostaglandins / Q000097:blood*; D013449:Sulfonamides / Q000494:pharmacology*; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D000096926:Benzenesulfonamides
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin; D002227:Carbazoles; D000077239:Meloxicam; D011453:Prostaglandins; D013449:Sulfonamides; D013843:Thiazines; D013844:Thiazoles; C007005:carprofen; C471996:deracoxib; D000096926:Benzenesulfonamides