Effects of a specific thromboxane synthetase inhibitor in equine endotoxaemia

Sparing the gut: COX-2 inhibitors herald a new era for treatment of horses with surgical colic

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to manage a wide variety of conditions in horses, including management of colic. Flunixin meglumine is by far the most commonly used drug in the control of colic pain and inflammation and has become a go-to for not only veterinarians but also horse-owners and nonmedical equine professionals. NSAID use, however, has always been controversial in critical cases due to a high risk of adverse effects associated with their potent cyclo-oxygenase (COX) inhibition. There are two important COX isoenzymes: COX-1 is generally beneficial for normal renal and gastrointestinal functions and COX-2 is associated with the pain and inflammation of disease. Newer selective NSAIDs can target COX-2-driven pathology while sparing important COX-1-driven physiology, which is of critical importance in horses with severe gastrointestinal disease. Emerging research suggests that firocoxib, a COX-2-selective NSAID labelled for use in horses, may be preferable for use in colic cases in spite of the decades-long dogma that flunixin saves lives.

Effects of clopidogrel on horses with experimentally induced endotoxemia

OBJECTIVE

To evaluate the effects of clopidogrel on clinical and clinicopathologic variables in healthy horses with experimentally induced endotoxemia.

ANIMALS

12 adult mares. Procedures-Horses were assigned with a randomization procedure to receive clopidogrel (4 mg/kg, once, then 2 mg/kg, q 24 h; n = 6) or a placebo (6) through a nasogastric tube. After 72 hours of treatment, horses received lipopolysaccharide (LPS; 30 ng/kg, IV). Heart rate, respiratory rate, rectal temperature, CBC variables, plasma fibrinogen concentration, serum tumor necrosis factor-α concentration, plasma von Willebrand factor concentration, and measures of platelet activation (including ADP- and collagen-induced platelet aggregation and closure times, thrombelastography variables, and results of flow cytometric detection of platelet membrane P-selectin, phosphatidylserine, and microparticles) were determined at various times before and after LPS administration by investigators unaware of the treatment groups. Statistical analyses were performed with repeated-measures ANOVA.

RESULTS

4 of 6 clopidogrel-treated horses had significant decreases in ADP-induced platelet aggregation before and after LPS administration. Heart rate increased significantly after LPS administration only for the placebo group. No significant differences were detected between groups for CBC variables, closure time, and plasma concentration of fibrinogen or serum concentration of tumor necrosis factor-α, and no clinically relevant differences were detected for other hemostatic variables.

CONCLUSIONS AND CLINICAL RELEVANCE

In this study, administration of LPS did not induce platelet hyperreactivity in horses on the basis of measures of platelet adhesion, aggregation, degranulation, and procoagulant activity. Administration of clopidogrel was associated with variable platelet antiaggregatory activity and attenuated some clinical signs of endotoxemia.

The effect of Toxoplasma gondii infection in flunixin meglumine treated pregnant ewes as monitored by plasma levels of 15-ketodihydroprostaglandin F2 alpha, progesterone, oestrone sulphate and ultrasound scanning

The aim of this study was to examine the endocrinological response (15-ketodihydro-PGF2 alpha, progesterone and oestrone sulphate) of pregnant ewes which were constantly treated with flunixin meglumine (FM) after infection with Toxoplasma gondii. Seven Swedish Peltsheep ewes were dosed orally with 2,000 T. gondii oocysts at 90.5 (82-94) days of pregnancy. The ewes were treated with FM, 1 mg/kg, intramuscularly twice a day, starting one day before infection until the end of the gestation period. Further three ewes were treated with FM alone during the corresponding time of pregnancy. Another four ewes were used as uninfected and untreated controls. All infected ewes developed antibodies to T. gondii and aborted, but the FM treated control group and the non-treated control group, which remained seronegative, delivered the lambs in the normal gestation range. No early abortions (less than 10 days after infection) were seen in the infected group. The endocrinological changes reflected the pathological changes in the uterus and foetuses. FM could neither completely inhibit prostaglandin release during abortion nor the physiological change of the hormone before parturition even though it depressed prostaglandin release before abortion or parturition and eliminated fever. The infectious process caused by the organism was probably not affected. FM treatment alone had no observed negative effects on pregnant ewes and their foetuses.