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John F Marshall - One of the best experts on this subject based on the ideXlab platform.

  • effect of flunixin meglumine and Firocoxib on ex vivo cyclooxygenase activity in horses undergoing elective surgery
    American Journal of Veterinary Research, 2015
    Co-Authors: Marco Duz, T D H Parkin, Rose M Cullander, John F Marshall
    Abstract:

    OBJECTIVE To evaluate ex vivo cyclooxygenase (COX) inhibition and compare in vitro and ex vivo COX-1 inhibition by flunixin meglumine and Firocoxib in horses. ANIMALS 4 healthy horses for in vitro experiments and 12 healthy horses (6 males and 6 females; 5 Thoroughbreds, 5 Warmbloods, and 2 ponies) undergoing elective surgery for ex vivo experiments. PROCEDURES 12 horses received flunixin meglumine (1.1 mg/kg, IV, q 12 h) or Firocoxib (0.09 mg/kg, IV, q 24 h). Blood samples were collected before (baseline) and 2 and 24 hours after NSAID administration. Prostanoids (thromboxane B2, prostaglandin E2, and prostaglandin E metabolites) served as indicators of COX activity, and serum drug concentrations were measured by use of high-performance liquid chromatography. An in vitro coagulation-induced thromboxane B2 assay was used to calculate drug concentration-COX-1 inhibition curves. Effect of time and treatment on COX activity was determined. Agreement between in vitro and ex vivo measurement of COX activity wa...

  • effect of phenylbutazone flunixin meglumine and Firocoxib on ex vivo cyclo oxygenase activity in horses undergoing elective surgery
    Equine Veterinary Journal, 2013
    Co-Authors: Marco Duz, T D H Parkin, John F Marshall
    Abstract:

    Aims Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the production of prostaglandins and other inflammatory mediators by inhibiting the activity of the cyclo-oxygenase enzymes (COX). Two major isoforms of COX enzymes exist: COX-2, which is expressed during the inflammatory response, and COX-1, which is responsible for the physiological production of prostaglandin that regulates tissue homeostasis. The study aims to evaluate the effect of Firocoxib ex vivo in the horse as, to the authors' knowledge, published studies assess its effect only in vitro. Methods Horses (n = 18) undergoing elective surgery were recruited and allocated to treatment groups depending on clinician preference (1) phenylbutazone (4.4 mg/kg bwt i.v. b.i.d.), (2) flunixin meglumine (FM, 1.1 mg/kg bwt i.v. b.i.d.) and (3) Firocoxib (FIR, 0.1 mg/kg bwt i.v. s.i.d.). Residual blood samples were collected prior to NSAIDs (T0), 2 h after NSAIDs (T2), and 24 h following surgery (T24). The COX activity was measured using validated immune-enzymatic assays. A Kruskall–Wallis test was used to determine the effect of time and treatment on COX-1 and COX-2 activity. Bonferroni corrections were used to identify the level of significance accounting for multiple comparisons (P<0.017). Results At T2 and T24, the relative COX-1 activity was significantly greater in horses receiving Firocoxib compared with horses receiving either phenylbutazone (P<0.008) or flunixin meglumine (P<0.005). At T2 and T24, COX-1 activity was reduced (compared with baseline) in horses receiving phenylbutazone or flunixin meglumine. The effect on COX-2 activity was not significantly different between drugs (P = 0.471). Conclusions and practical significance Cyclo-oxygenase selectivity of Firocoxib is demonstrated ex vivo. Firocoxib is as effective as phenylbutazone or flunixin meglumine in modulating the production of prostaglandins by COX-2 isoenzyme, whilst the physiological action of COX-1 isoenzyme is preserved with Firocoxib, but not with phenylbutazone and flunixin ex vivo. Ethical animal research Study approved by Ethics and Welfare Committee - School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow. Sources of funding: Funding provided by John Crawford Endowment Fund, and Mrs I.J. Gates Charity Fund, University of Glasgow. Competing interests: None.

Peter Hanson - One of the best experts on this subject based on the ideXlab platform.

  • field trial validation of the efficacy and acceptability of Firocoxib a highly selective cox 2 inhibitor in a group of 96 lame horses
    Journal of Equine Veterinary Science, 2010
    Co-Authors: Marc Koene, Peter Hanson, Xavier Goupil, Clemens Kampmann, Davida Denton, M Pollmeier
    Abstract:

    Abstract The objective was to generate evidence for clinical efficacy and acceptability of a second generation coxib, Firocoxib, administered orally for 14 days to lame horses under field conditions compared with a classic nonsteroidal anti-inflammatory drug, vedaprofen, in a prospective, randomized, controlled, double-blinded, multicenter field trial. Ninety-six client-owned horses with American Association of Equine Practitioners score of at least grade 3 lameness or grade 2 lameness plus at least a score of 2 for either pain on palpation, range of motion, or joint swelling were analyzed. Horses were administered 0.1 mg/kg Firocoxib orally at 24 hour intervals (n = 48) or 1.0 mg/kg vedaprofen paste at 12 hour intervals for 14 days (single loading dose of 2.0 mg/kg vedaprofen) (n = 48). Physical examinations and lameness evaluations were conducted on Day 1 (V1, before treatment) and on Days 7 (V2) and 14 (V3). Blood chemistry and hematology profiles were also evaluated. With regard to the primary variable, clinical improvement, 83% of the Firocoxib-treated horses improved at V3 compared with 65% of vedaprofen-treated horses improved meeting the criteria defined to demonstrate noninferiority of Firocoxib to vedaprofen. Health and behavioral abnormalities for side effect detection occurred at the rate of 2% (1 horse) and 8% (4 horses) for Firocoxib- and vedaprofen-treated horses, respectively. Changes in hematology and blood chemistry values from V1 to V3 were not significantly different between treatment groups. Firocoxib, formulated as an oral paste was highly effective, well tolerated, and acceptable for the control of pain and inflammation associated with lameness in horses under field conditions.

  • The use of force plate measurements to titrate the dosage of a new cox-2 inhibitor in lame horses.
    Equine veterinary journal, 2009
    Co-Authors: Willem Back, M Pollmeier, C. G. Macallister, M. C. V. Van Heel, Peter Hanson
    Abstract:

    Reasons for performing study: Lameness is a highly prevalent condition in horses and the principal cause of removal from athletic activity. In clinical studies to evaluate nonsteroidal anti-inflammatory drug therapies, force plates are commonly used to assess improvement of lameness objectively. Hypothesis: To use a force plate to determine the optimal dose of a new COX-2 inhibitor (Firocoxib) that will reduce lameness, when administered orally to horses once daily. Methods: Sixty-four horses that exhibited chronic lameness presumed due to osteoarthritis, including navicular disease, in at least one of the frontlimbs and at a stable level of severity, were included. Horses were treated per os s.i.d. for 7 days as follows: vehicle control, Firocoxib at 0.05, 0.1 or 0.25 mg/kg bwt. Force plate analysis of each horse was done for the selected (most) lame frontlimb at trot. Once between Days -19 and -4 (initial examination), and again on Day -2 or -1 (baseline), pretreatment force plate assessments were performed, and thereafter horses were assessed on Days 0, 2 and 6, approximately 10 h post treatment each time. Peak vertical force (PVF) and lameness grades at initial examination and at baseline, and their change from baseline in the 4 different treatment groups were analysed statistically at a significance level of P

  • pharmacokinetics of Firocoxib after administration of multiple consecutive daily doses to horses
    American Journal of Veterinary Research, 2008
    Co-Authors: Laura Letendre, Valerie Kvaternick, James Fischer, Scott R Mcclure, Ronald K Tessman, Peter Hanson
    Abstract:

    Objective—To determine pharmacokinetic parameters and variables, Firocoxib concentrations in urine and plasma, urine-to-plasma ratios, and the urine depletion profile of Firocoxib and to evaluate whether the pharmacokinetic behavior of Firocoxib was governed by linear processes after multiple doses of Firocoxib were administered IV and orally. Animals—6 healthy female horses (5 Paint horses and 1 Quarter Horse) in experiment 1 and 12 healthy male and female horses in experiment 2. Procedures—In experiment 1, 6 horses were orally administered Firocoxib paste once daily for 12 consecutive days, and plasma and urine samples were obtained and analyzed. In a second experiment, 12 horses received IV injections of Firocoxib solution once daily for 9 consecutive days, and plasma was obtained and analyzed. Results—Mean ± SD clearance and steady-state volume of distribution of Firocoxib were 40.5 ± 14.7 mL/h/kg and 2.3 ± 0.7 L/kg, respectively. Mean half-life was 44.2 ± 21.6 hours and 36.5 ± 9.5 hours for IV and or...

  • comparison of the effects of Firocoxib carprofen and vedaprofen in a sodium urate crystal induced synovitis model of arthritis in dogs
    Research in Veterinary Science, 2008
    Co-Authors: H A W Hazewinkel, Matthias Pollmeier, Walter E Van Den Brom, L F H Theyse, Peter Hanson
    Abstract:

    A randomized, placebo-controlled, four-period cross-over laboratory study involving eight dogs was conducted to confirm the effective analgesic dose of Firocoxib, a selective COX-2 inhibitor, in a synovitis model of arthritis. Firocoxib was compared to vedaprofen and carprofen, and the effect, defined as a change in weight bearing measured via peak ground reaction, was evaluated at treatment dose levels. A lameness score on a five point scale was also assigned to the affected limb. Peak vertical ground reaction force was considered to be the most relevant measurement in this study. The Firocoxib treatment group performed significantly better than placebo at the 3 h post-treatment time point and significantly better than placebo and carprofen at the 7 h post-treatment time point. Improvement in lameness score was also significantly better in the dogs treated with Firocoxib than placebo and carprofen at both the 3 and 7 h post-treatment time points.

  • pharmacokinetics and metabolism of orally administered Firocoxib a novel second generation coxib in horses
    Journal of Veterinary Pharmacology and Therapeutics, 2007
    Co-Authors: Valerie Kvaternick, James Fischer, M Pollmeier, Peter Hanson
    Abstract:

    The primary objective of this study was to determine the pharmacokinetic profile of Firocoxib, a novel second generation coxib, in horses. Horses were administered either a single oral or intravenous dose of Firocoxib at 0.1 mg/kg in a two-period crossover study with 12 animals. The dosage was based on previously determined pharmacodynamic parameters. Oral Firocoxib was well absorbed with an average bioavailability (absolute) of 79% and a Cmax of 75 ng/mL at 3.9 h. The average elimination half-life was 30 h. Following intravenous administration the average Cmax was 210 ng/mL and the elimination half-life was 34 h. The area under the curve [AUC(0-tlast)] was 1.8 microg.h/mL for the oral dose and 2.3 microg.h/mL for the intravenous dose. Firocoxib was widely distributed with a volume of distribution value of 1.7 L/kg for the intravenous dose. Biotransformation of Firocoxib was via dealkylation and glucuronidation to inactive metabolites, namely descyclopropylmethylFirocoxib and its glucuronide conjugate. Urinary excretion was the major route of elimination, and the clearance rate was 37 mL/h/kg.

Francesca Millanta - One of the best experts on this subject based on the ideXlab platform.

  • clinical outcome and cyclo oxygenase 2 expression in five dogs with solar dermatitis actinic keratosis treated with Firocoxib
    Veterinary Dermatology, 2013
    Co-Authors: Francesco Albanese, Francesca Abramo, Chiara Caporali, Gaia Vichi, Francesca Millanta
    Abstract:

    Background The conversion of arachidonic acid into prostaglandin is catalysed by the cyclo-oxygenases (COX-1/COX-2). Several studies indicate that COX-2 is overexpressed in actinic keratosis in humans and dogs. Firocoxib is a COX-2-selective inhibitor that blocks the biochemical activity of COX-2. Hypothesis/objectives To evaluate the efficacy of Firocoxib (5 mg/kg orally once daily) for the treatment of dogs with solar dermatitis/actinic keratosis. Methods Firocoxib 5 mg/kg was given orally once daily for 180 days to five dogs with clinical signs and histopathological lesions consistent with solar dermatitis/actinic keratosis. On days 0, 50 and 180, the severity of erythema, skin shine, induration and the number of comedones were evaluated by a clinical scoring system. On the same days, samples were collected for histopathology from 'target lesions' and COX-2 expression was evaluated by immunohistochemistry. Results The clinical follow-up showed that four of five dogs improved with the treatment; improvement in terms of histological findings was correlated with the regularization of the epidermal proliferation rather than the recovery of dermal changes. Conclusions and clinical importance A role for COX-2 might thus be hypothesized in the pathogenesis of canine solar dermatitis.

  • Clinical outcome and cyclo-oxygenase-2 expression in five dogs with solar dermatitis/actinic keratosis treated with Firocoxib
    'Wiley', 2013
    Co-Authors: Francesco Albanese, Francesca Abramo, Chiara Caporali, Gaia Vichi, Francesca Millanta
    Abstract:

    Background: The conversion of arachidonic acid into prostaglandin is catalysed by the cyclo-oxygenases (COX-1/COX-2). Several studies indicate that COX-2 is overexpressed in actinic keratosis in humans and dogs. Firocoxib is a COX-2-selective inhibitor that blocks the biochemical activity of COX-2. Hypothesis/Objectives: To evaluate the efficacy of Firocoxib (5 mg/kg orally once daily) for the treatment of dogs with solar dermatitis/actinic keratosis. Methods: Firocoxib 5 mg/kg was given orally once daily for 180 days to five dogs with clinical signs and histopathological lesions consistent with solar dermatitis/actinic keratosis. On days 0, 50 and 180, the severity of erythema, skin shine, induration and the number of comedones were evaluated by a clinical scoring system. On the same days, samples were collected for histopathology from 'target lesions' and COX-2 expression was evaluated by immunohistochemistry. Results: The clinical follow-up showed that four of five dogs improved with the treatment; improvement in terms of histological findings was correlated with the regularization of the epidermal proliferation rather than the recovery of dermal changes. Conclusions and clinical importance: A role for COX-2 might thus be hypothesized in the pathogenesis of canine solar dermatiti

Barbosa, Cristiane Moraes - One of the best experts on this subject based on the ideXlab platform.

  • Evaluations hematological and biochemical by the use of sodium diclofenac, meloxicam and Firocoxib in rats
    2010
    Co-Authors: Barbosa, Cristiane Moraes, Sakate Michiko, Camplesi, Annelise Carla, Vailati, Maria Do Carmo Fernandez, Moraes, Lívia Fagundes, Takahira, Regina Kiomi
    Abstract:

    This work has evaluated the hematological and biochemical profile by the use of sodium diclofenac, meloxicam and Firocoxib in Wistar rats. The rats were distributed in groups: G1 (control), G2 (diclofenac sodium: 15 mg/kg), G3 (meloxicam: 2.0 mg/ kg), G4 (meloxicam: 10.0 mg/ kg), G5 (Firocoxib: 5.0 mg/ kg) e G6 (Firocoxib: 25.0 mg/ kg). The drugs were administered intragastrically (gavage) once a day, during five days and evaluated in three moments: M1 (48 hours after the beginning of the treatment), M2 (96 hours after the beginning of the treatment) and M3 (72 hours after the ending of the treatment). In each moment of each group, five to seven animals were evaluated and laboratory exams were performed. There were no significant changes observed in the biochemical and hematological parameters by the use of meloxicam and Firocoxib. One of the effects of the sodium diclofenac was eritrogram variation as hematocrit, erythrocytes, hemoglobin decrease during the treatment. In addition, the platelets and total white blood cells counts did not change except for basophil. There was no changes in AST, ALP, GGT, urea, creatinine, sodium, potassium values. However, the values of protein, globulin and albumin decreased. It was concluded that diclofenac sodium does not provide large variations in the hemogram and biochemical profile than the meloxicam and Firocoxib do not provide delletery effects in laboratories tests

  • Avaliações hematológicas e bioquímicas do uso de diclofenaco de sódio, meloxicam e Firocoxibe em ratos
    Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia, 2010
    Co-Authors: Barbosa, Cristiane Moraes, Sakate Michiko, Camplesi, Annelise Carla, Vailati, Maria Do Carmo Fernandez, Moraes, Lívia Fagundes, Takahira, Regina Kiomi
    Abstract:

    This work has evaluated the hematological and biochemical profile by the use of sodium diclofenac, meloxicam and Firocoxib in Wistar rats. The rats were distributed in groups: G1 (control), G2 (diclofenac sodium: 15 mg/kg), G3 (meloxicam: 2.0 mg/ kg), G4 (meloxicam: 10.0 mg/ kg), G5 (Firocoxib: 5.0 mg/ kg) e G6 (Firocoxib: 25.0 mg/ kg). The drugs were administered intragastrically (gavage) once a day, during five days and evaluated in three moments: M1 (48 hours after the beginning of the treatment), M2 (96 hours after the beginning of the treatment) and M3 (72 hours after the ending of the treatment). In each moment of each group, five to seven animals were evaluated and laboratory exams were performed. There were no significant changes observed in the biochemical and hematological parameters by the use of meloxicam and Firocoxib. One of the effects of the sodium diclofenac was eritrogram variation as hematocrit, erythrocytes, hemoglobin decrease during the treatment. In addition, the platelets and total white blood cells counts did not change except for basophil. There was no changes in AST, ALP, GGT, urea, creatinine, sodium, potassium values. However, the values of protein, globulin and albumin decreased. It was concluded that diclofenac sodium does not provide large variations in the hemogram and biochemical profile than the meloxicam and Firocoxib do not provide delletery effects in laboratories tests.O presente trabalho avaliou os parâmetros hematológicos e bioquímicos do uso de diclofenaco de sódio, meloxicam e Firocoxibe em ratos Wistar. Os ratos foram distribuídos em grupos: G1 (controle), G2 (diclofenaco de sódio: 15 mg/kg), G3 (meloxicam: 2,0 mg/ kg), G4 (meloxicam: 10,0 mg/ kg), G5 (Firocoxibe: 5,0 mg/ kg) e G6 (Firocoxibe: 25,0 mg/ kg). Os fármacos foram administrados por via intragástrica (gavage) a cada 24 horas, durante cinco dias e avaliados em três momentos: M1 (48 horas após o início do tratamento), M2 (96 horas após o início do tratamento) e M3 (72 horas após o término do tratamento). Em cada momento de cada grupo, foram avaliados de cinco a sete animais e realizados os exames laboratoriais. Não foram observadas alterações significativas nos parâmetros bioquímicos e hematológicos com o uso de meloxicam e Firocoxibe. O diclofenaco de sódio produziu alterações no eritrograma (redução de hemácias, hematócrito e na taxa de hemoglobina) durante o tratamento e não alterou a contagem das plaquetas e leucometria, com exceção dos basófilos. Não produziu alterações nas atividades de AST, FA, GGT, ureia, creatinina, sódio e potássio. Entretanto, causou diminuições das proteínas plasmática e total sérica, albumina e globulina. Conclui-se que o diclofenaco de sódio não produz grandes alterações no hemograma e exames bioquímicos, enquanto que, o meloxicam e o Firocoxibe não produzem alterações e efeitos deletérios dose-dependentes nestes exames laboratoriais

  • Avaliações hematológicas e bioquímicas do uso de diclofenaco de sódio, meloxicam e Firocoxibe em ratos wistar
    Universidade Estadual Paulista (UNESP), 2008
    Co-Authors: Barbosa, Cristiane Moraes
    Abstract:

    O presente trabalho avaliou os parâmetros hematológicos e bioquímicos do uso de diclofenaco de sódio, meloxicam e Firocoxibe em ratos Wistar. Os ratos foram distribuídos em grupos: G1 (controle), G2 (diclofenaco de sódio: 15 mg/kg), G3 (meloxicam: 2,0 mg/ kg), G4 (meloxicam: 10,0 mg/ kg), G5 (Firocoxibe: 5,0 mg/ kg) e G6 (Firocoxibe: 25,0 mg/ kg). Os fármacos foram administrados por via intragástrica (gavage) a cada 24 horas, durante 5 dias e avaliados em 3 momentos: M1 (48 horas após o início do tratamento), M2 (96 horas após o início do tratamento) e M3 (72 horas após o término do tratamento). Em cada momento de cada grupo, foram avaliados de 5 a 7 animais e realizados os exames laboratoriais. Não foram observadas alterações significativas nos parâmetros bioquímicos e hematológicos com o uso de meloxicam e Firocoxibe. O diclofenaco de sódio produziu alterações no eritrograma (redução do hematócrito e na taxa de hemoglobina) durante o tratamento e não alterou a contagem das plaquetas e leucometria, com exceção dos basófilos. Não produziu alterações nas atividades de AST, FA, GGT, uréia, creatinina e potássio. Entretanto, causou diminuições temporárias da albumina e globulina e elevações nos valores séricos de sódio. Conclui-se que o diclofenaco de sódio não produz grandes alterações no hemograma e exames bioquímicos, mas deve ser usado com cautela em roedores. O meloxicam e Firocoxibe não produzem alterações e efeitos deletérios dose-dependentes no hemograma e parâmetros bioquímicos, portanto são drogas seguras em ratos.This work has evaluated the hematological and biochemical profile by the use of sodium diclofenac, meloxicam and Firocoxib in Wistar rats. The rats were distributed in groups: G1 (control), G2 (diclofenac sodium: 15 mg/kg), G3 (meloxicam: 2,0 mg/ kg), G4 (meloxicam: 10,0 mg/ kg), G5 (Firocoxib: 5,0 mg/ kg) e G6 (Firocoxib: 25,0 mg/ kg). The drugs were administered intragastrically (gavage) once a day, during 5 days and evaluated in 3 moments: M1 (48 hours after the beginning of the treatment), M2 (96 hours after the beginning of the treatment) and M3 (72 hours after the ending of treatment). In each moment of each group, 5 to 7 animals were evaluated and laboratory exams were performed. There were no significant changes observed in the biochemical and hematological parameters by the use of meloxicam and Firocoxib. One of effects of the sodium diclofenac was eritrogram variation as hematocrit and hemoglobin decrease during the treatment. In addition, the platelets and leukogram counts did not change except for basophil. There was no changes in AST, ALP, GGT, urea, creatinine and potassium values. However, the values of globulim and albumim decreased temporarily and the serum values of sodium incresead. It can concluded that diclofenac sodium does not provide large variations in the hemogram and biochemical profile, but it must be used with care in rodents. The meloxicam and Firocoxib does not provide delletery effects in the hemogram and biochemical profile, thus these drugs can be considered safe in rats.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Marco Duz - One of the best experts on this subject based on the ideXlab platform.

  • effect of flunixin meglumine and Firocoxib on ex vivo cyclooxygenase activity in horses undergoing elective surgery
    American Journal of Veterinary Research, 2015
    Co-Authors: Marco Duz, T D H Parkin, Rose M Cullander, John F Marshall
    Abstract:

    OBJECTIVE To evaluate ex vivo cyclooxygenase (COX) inhibition and compare in vitro and ex vivo COX-1 inhibition by flunixin meglumine and Firocoxib in horses. ANIMALS 4 healthy horses for in vitro experiments and 12 healthy horses (6 males and 6 females; 5 Thoroughbreds, 5 Warmbloods, and 2 ponies) undergoing elective surgery for ex vivo experiments. PROCEDURES 12 horses received flunixin meglumine (1.1 mg/kg, IV, q 12 h) or Firocoxib (0.09 mg/kg, IV, q 24 h). Blood samples were collected before (baseline) and 2 and 24 hours after NSAID administration. Prostanoids (thromboxane B2, prostaglandin E2, and prostaglandin E metabolites) served as indicators of COX activity, and serum drug concentrations were measured by use of high-performance liquid chromatography. An in vitro coagulation-induced thromboxane B2 assay was used to calculate drug concentration-COX-1 inhibition curves. Effect of time and treatment on COX activity was determined. Agreement between in vitro and ex vivo measurement of COX activity wa...

  • effect of phenylbutazone flunixin meglumine and Firocoxib on ex vivo cyclo oxygenase activity in horses undergoing elective surgery
    Equine Veterinary Journal, 2013
    Co-Authors: Marco Duz, T D H Parkin, John F Marshall
    Abstract:

    Aims Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the production of prostaglandins and other inflammatory mediators by inhibiting the activity of the cyclo-oxygenase enzymes (COX). Two major isoforms of COX enzymes exist: COX-2, which is expressed during the inflammatory response, and COX-1, which is responsible for the physiological production of prostaglandin that regulates tissue homeostasis. The study aims to evaluate the effect of Firocoxib ex vivo in the horse as, to the authors' knowledge, published studies assess its effect only in vitro. Methods Horses (n = 18) undergoing elective surgery were recruited and allocated to treatment groups depending on clinician preference (1) phenylbutazone (4.4 mg/kg bwt i.v. b.i.d.), (2) flunixin meglumine (FM, 1.1 mg/kg bwt i.v. b.i.d.) and (3) Firocoxib (FIR, 0.1 mg/kg bwt i.v. s.i.d.). Residual blood samples were collected prior to NSAIDs (T0), 2 h after NSAIDs (T2), and 24 h following surgery (T24). The COX activity was measured using validated immune-enzymatic assays. A Kruskall–Wallis test was used to determine the effect of time and treatment on COX-1 and COX-2 activity. Bonferroni corrections were used to identify the level of significance accounting for multiple comparisons (P<0.017). Results At T2 and T24, the relative COX-1 activity was significantly greater in horses receiving Firocoxib compared with horses receiving either phenylbutazone (P<0.008) or flunixin meglumine (P<0.005). At T2 and T24, COX-1 activity was reduced (compared with baseline) in horses receiving phenylbutazone or flunixin meglumine. The effect on COX-2 activity was not significantly different between drugs (P = 0.471). Conclusions and practical significance Cyclo-oxygenase selectivity of Firocoxib is demonstrated ex vivo. Firocoxib is as effective as phenylbutazone or flunixin meglumine in modulating the production of prostaglandins by COX-2 isoenzyme, whilst the physiological action of COX-1 isoenzyme is preserved with Firocoxib, but not with phenylbutazone and flunixin ex vivo. Ethical animal research Study approved by Ethics and Welfare Committee - School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow. Sources of funding: Funding provided by John Crawford Endowment Fund, and Mrs I.J. Gates Charity Fund, University of Glasgow. Competing interests: None.