Phenylbutazone is a non-steroidal anti-inflammatory drug (NSAID) commonly used in horses to manage pain and inflammation associated with musculoskeletal disorders. It functions by inhibiting the cyclooxygenase enzymes (COX-1 and COX-2), which play a role in the inflammatory process. Phenylbutazone is administered in various formulations, including oral and injectable forms, and is often used in the treatment of conditions such as arthritis, laminitis, and soft tissue injuries. The pharmacokinetics, therapeutic effects, and potential side effects, such as gastrointestinal irritation and renal impairment, are subjects of ongoing research. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacology, clinical applications, and safety considerations of phenylbutazone in equine medicine.
Raidal SL, Hughes KJ, Charman AL, Nielsen SG, Phillips JK, Noble GK.To compare the effects of 2 NSAIDs (phenylbutazone and meloxicam) on renal function in horses. Methods: 9 Thoroughbred or Standardbred mares (mean ± SD age, 5.22 ± 1.09 years [range, 2 to 12 years]; mean body weight, 470 ± 25 kg [range, 442 to 510 kg]). Methods: A randomized blinded placebo-controlled crossover study was conducted to examine the effects of treatment with phenylbutazone, meloxicam, or a placebo (control solution) on renal responses to the administration of furosemide, dobutamine, and exercise (15 minutes at 60% of maximum heart rate). Renal function was assessed by use of bi...
Sanchez LC, Robertson SA.Currently, approaches to pain control in horses are a mixture of art and science. Recognition of overt pain behaviours, such as rolling, kicking at the abdomen, flank watching, lameness or blepharospasm, may be obvious; subtle signs of pain can include changes in facial expression or head position, location in the stall and response to palpation or human interaction. Nonsteroidal anti-inflammatory drugs (i.e. phenylbutazone, flunixin meglumine and firocoxib), opioids (i.e. butorphanol, morphine and buprenorphine) and α2 -adrenergic agonists (i.e. xylazine, detomidine, romifidine and medetomid...
Wohlfender FD, Doherr MG, Driessen B, Hartnack S, Johnston GM, Bettschart-Wolfensberger R.Multicentre Confidential Enquiries into Perioperative Equine Fatalities (CEPEF) have not been conducted since the initial CEPEF Phases 1-3, 20 years ago. Objective: To collect data on current practice in equine anaesthesia and to recruit participants for CEPEF-4. Methods: Online questionnaire survey. Methods: An online questionnaire was prepared and the link distributed internationally to veterinarians possibly performing equine anaesthesia, using emails, posters, flyers and an editorial. The questionnaire included 52 closed, semiclosed and open questions divided into 8 subgroups: demographic ...
de Grauw JC, van Loon JP, van de Lest CH, Brunott A, van Weeren PR.Although phenylbutazone (PBZ) is commonly used in equine orthopaedic practice, little is known about its in vivo effects on joint inflammation and cartilage turnover. This study investigates the effects of PBZ on inflammatory parameters, matrix metalloproteinase (MMP) activity and cartilage biomarkers in equine joints with acute synovitis. In a two-period cross-over study, transient synovitis was induced at T = 0 h in the middle carpal joint of seven ponies by lipopolysaccharide (LPS) injection. Ponies received PBZ (2 mg/kg PO twice daily) or placebo for 1 week, starting at T = 2 h. Ar...
Kivett L, Taintor J, Wright J.Simultaneous administration of a nonselective COX inhibitor and a COX-2 specific NSAID has not been previously reported in horses. The goal of this study was to determine the safety of a 10-day dosage regimen of phenylbutazone and firocoxib, both at their standard dosages, in horses. Six horses were administered 2.2 mg/kg of phenylbutazone and 0.1 mg/kg of firocoxib by mouth, daily for 10 days. Horses were assessed daily for changes in behavior, appetite, fecal consistency, signs of abdominal pain, and oral mucous membrane ulceration. Horses were assessed prior to and on the last day of treatm...
Heffron B, Taddei L, Benoit M, Negrusz A.The use of nonsteroidal antiinflammatory drugs in racehorses is allowed under most jurisdictions. Furosemide is administered to treat exercise-induced pulmonary hemorrhage. To help distinguish between therapeutic and illegal uses, racing regulatory bodies have set thresholds in serum for several drugs. The method for the simultaneous detection and quantification of furosemide, flunixin, ketoprofen, phenylbutazone and oxyphenbutazone using 500 µL of serum, and liquid extraction using diethyl ether : hexanes : dichloromethane followed by liquid chromatography tandem mass spectrometry quantitati...
Benmansour P, Duke-Novakovski T.A 10-year old Arabian mare had a slow-growing mass on the lower right mandible and required a large partial mandibulectomy. Methods: No abnormalities were detected apart from the mass. Results: A temporary tracheostomy was performed pre-operatively. Anesthesia was induced with xylazine followed by ketamine and diazepam. For 13Â hours, anesthesia was maintained using sevoflurane, dexmedetomidine and remifentanil infusions, with the exception of surgical preparation time. Intra-operatively, ventilation was delivered through the cuffed tracheotomy tube. Heart and respiratory rates, ECG, arterial ...
Lees P, Toutain PL.The presence of horse meat in food products destined for human consumption and labelled as beef has raised several concerns of public interest. This review deals solely with one aspect of these concerns; samples of equine tissue from horses destined for the human food chain have tested positive for the non-steroidal anti-inflammatory drug, phenylbutazone. The safety of some or all such foods for human consumers is a major concern, because it was shown many years ago that phenylbutazone therapy in humans can be associated with life threatening blood dyscrasias. As an initial basis for assessing...
Dabareiner RM, Chaffin MK, Quirham H, Carter GK.4 horses with enthesopathy and desmitis of the medial collateral ligament of the cubital joint were examined. Results: All 4 horses had a history of acute, severe, unilateral forelimb lameness and had signs of pain during manipulation of the affected upper forelimb; 2 also had swelling in the axillary region. There was no improvement in lameness after diagnostic local analgesia below the carpal region, and 1 of 4 horses had mild improvement after cubital joint analgesia. Radiography revealed enthesophyte formation on the radial tuberosity and linear mineralization of the medial collateral liga...
Guedes AG, Morisseau C, Sole A, Soares JH, Ulu A, Dong H, Hammock BD.A 4-year old, 500 kg Thoroughbred female horse diagnosed with bilateral forelimb laminitis and cellulitis on the left forelimb became severely painful and refractory to non-steroidal anti-inflammatory therapy (flunixin meglumine on days 1, 2, 3 and 4; and phenylbutazone on days 5, 6 and 7) alone or in combination with gabapentin (days 6 and 7). Methods: Pain scores assessed independently by three individuals with a visual analog scale (VAS; 0 = no pain and 10 = worst possible pain) were 8.5 on day 6, and it increased to 9.5 on day 7. Non-invasive blood pressure monitoring revealed severe hyper...
D'Arcy-Moskwa E, Noble GK, Weston LA, Boston R, Raidal SL.Newer NSAIDs that more selectively target the induced isoform of the cyclooxygenase enzyme (COX2) activity might reduce adverse effects while preserving therapeutic benefits of these drugs. Objective: To compare the effect of oral administration of multiple dose rates of meloxicam and phenylbutazone (PBZ) on gastric mucosal integrity in horses. Methods: Twenty-five light breed horses. Methods: In vivo toxicity study. Horses were randomly assigned to 5 treatment groups, receiving placebo, PBZ (4.4 mg/kg PO q12h day 1, 2.2 mg/kg PO q12h for 4 days, 2.2 mg/kg PO q24h for 9 days), or 3 dose rates ...
van Loon JP, de Grauw JC, Brunott A, Weerts EA, van Weeren PR.Intra-articular injection of opioids provides analgesia in painful equine joints and μ-opioid receptors (MORs) have been demonstrated in equine synovial membranes. The aim of this study was to determine whether acute inflammatory conditions will lead to up-regulation of MOR in equine synovial membranes and whether anti-inflammatory treatment can prevent any such upregulation. In a two-period, blinded, placebo-controlled randomised cross-over design, lipopolysaccharide (LPS, 1.0 ng) was injected into the left or right middle carpal joint of seven healthy ponies. Arthroscopy and synovial membra...
Noble G, Edwards S, Lievaart J, Pippia J, Boston R, Raidal SL.Safety of meloxicam, a potent NSAID with selective COX-2 inhibition, has not been evaluated in horses. Objective: To evaluate pharmacokinetics and safety of single and repeated oral doses of meloxicam in adult horses. Methods: Forty-nine healthy, university-owned adult lightbreed horses. Methods: Study conducted in 2 parts. Part I addressed pharmacokinetics of single oral dose meloxicam (0.6 mg/kg) in 16 horses. Part II, 33 horses were randomly assigned to 5 treatment groups to assess prolonged administration (0.6 mg/kg PO q24h for 6 weeks, n = 7) or higher doses (1.8 mg/kg, n = 7, or 3.0 mg/k...
Vallance SA, Lumsden JM, Begg AP, O'Sullivan CB.To review eight horses diagnosed with idiopathic haemarthrosis and to describe the intra-articular use of yttrium-90 ((90) Y) and methylprednisolone acetate (MPA) in recurrent haemarthrosis cases. Methods: Retrospective case series. Methods: The medical records, diagnostic images, histopathology and outcome of all horses diagnosed with idiopathic haemarthrosis between 1998 and 2010 were reviewed. Results: Four Thoroughbred racehorses with haemarthrosis of the antebrachiocarpal joint had severe acute lameness (median, grade 4) and marked joint effusion after high-speed exercise. Another four ho...
Nieto JE, Aleman M, Anderson JD, Fiack C, Snyder JR.To assess gene expressions of cyclooxygenase-1 and -2 in oral, glandular gastric, and urinary bladder mucosae and determine the effect of oral administration of phenylbutazone on those gene expressions in horses. Methods: 12 healthy horses. Methods: Horses were allocated to receive phenylbutazone or placebo (6 horses/group); 1 placebo-treated horse with a cystic calculus was subsequently removed from the study, and those data were not analyzed. In each horse, the stomach and urinary bladder were evaluated for ulceration via endoscopy before and after experimental treatment. Oral, glandular gas...
Foreman JH, Ruemmler R.Using an adjustable heart bar shoe model of foot pain, the objective of this study was to test the hypothesis that the combined use of phenylbutazone (PBZ) and flunixin meglumine (FM) would prove more efficacious in alleviating lameness than either drug alone. Methods: One hour after induction of lameness at weekly intervals, 8 healthy adult Thoroughbred horses randomly underwent one of 4 i.v. treatments: saline (SAL) placebo (1 ml/45 kg bwt), PBZ (4.4 mg/kg bwt), FM (1.1 mg/kg bwt) or PBZ+FM (at the same dosages as given individually). Heart rate (HR) and lameness score (LS) responses were as...
Benbarek H, Ayad A, Deby-Dupont G, Boukraa L, Serteyn D.The purpose of this study was to explore the potential modulation of equine neutrophil oxidative burst by a series of classical NSAIDs which was subsequently monitored by the luminol or lucigenin-enhanced chemiluminescence (CL) technique. A significant dose-dependent inhibition of the luminol CL was observed with the majority of investigated drugs. This inhibition was very significant for phenylbutazone and Indomethacin; while for aspirin, a higher concentration is required. The action of Ketoprofen was significant during the first 5 min and only when the concentration was above 1 mM. Indometh...
Aleman M, Nieto JE, Higgins JK.A 15-year-old Quarter Horse gelding and a 26-year-old Thoroughbred gelding were evaluated because of hematuria of 4 to 6 days' duration following prolonged oral administration of phenylbutazone. Results: The horses had received either treatment with phenylbutazone for 3 months or intermittent long-term phenylbutazone treatment prior to development of hematuria. Each horse was systemically stable but had orthopedic or neurologic problems. Clinicopathologic findings included normochromic normocytic anemia in both horses and hypoalbuminemia and high BUN concentration in 1 horse. In both horses, u...
Kruger K, Stegmann GF, Becker PJ.To characterize the cardiorespiratory and electrocardiographic effects of the combined administration of phenylbutazone and romifidine. Methods: Prospective four-period, four-treatment, blinded, randomized, crossover trial. Methods: Five, healthy, mixed breed horses. Methods: Prior to treatment administration, a catheter was introduced into the intra-thoracic cranial vena cava via the jugular vein and a subcutaneously located carotid artery was catheterised. All treatments were administered intravenously (IV) and consisted of saline placebo (PLC), phenylbutazone (PBZ, 4.4 mg kg(-1) ) romifidin...
Foreman JH, Grubb TL, Inoue OJ, Banner SE, Ball KT.Objective blinded efficacy data during exercise are lacking on the use of single-dose i.v. nonsteroidal anti-inflammatory drugs (NSAIDs) before, during and after exercise. Objective: Single i.v. doses of either phenylbutazone (PBZ) or flunixin meglumine (FM) would prove more efficacious than negative saline control (SAL) before, during and after exercise in a reversible model of foot lameness. Methods: Six Quarter Horse mares had lameness induced by tightening a set screw against a heart bar shoe 1 h prior to treatment. Randomised blinded treatments included PBZ (4.4 mg/kg bwt i.v.), FM (1.1 m...
Waran N, Williams VM, Clarke N, Bridge IS.To explore attitudes towards and use of analgesia in horses by veterinarians in New Zealand. Methods: A postal questionnaire was sent out to 457 veterinarians identified as working with horses in New Zealand. Questions covered demographics and practice data; analgesic drugs available for use and used in practice; analgesic management of specific conditions including assessment of pain, drugs used, and frequency of cases; factors influencing the choice and use of analgesic agents; and attitudes and personal experience. Results: Ninety-seven questionnaires containing useable data were received, ...
Müller M, Raabe O, Addicks K, Wenisch S, Arnhold S.In equine medicine, stem cell therapies for orthopaedic diseases are routinely accompanied by application of NSAIDs (non-steroidal anti-inflammatory drugs). Thus, it has to be analysed how NSAIDs actually affect the growth and differentiation potential of MSCs (mesenchymal stem cells) in vitro in order to predict the influence of NSAIDs such as phenylbutazone, meloxicam, celecoxib and flunixin on MSCs after grafting in vivo. The effects of NSAIDs were evaluated regarding cell viability and proliferation. Additionally, the multilineage differentiation capacity and cell migration was analysed. N...
Thomas DP, Foley JP.Detection of prohibited substances in equestrian sports typically involves time-consuming and tedious sample-preparation methods. Micellar LC (MLC) allows for direct injection of equine serum to detect prohibited NSAIDs. Results: The method was linear over the range of standards examined, with recoveries of 94.2-95.1% for phenylbutazone (12-18 µg/ml), and 83.9-88.7% and 87.9-105.0% for diclofenac and flunixin, respectively (0.1-1.2 µg/ml). The limit of detection was 0.1 µg/ml for all compounds and the limit of quantitation was 0.2 µg/ml for phenylbutazone and 0.3 µg/ml for diclofenac and ...
Authie EC, Garcia P, Popot MA, Toutain PL, Doucet M.Equine antidoping rules were established to prevent a horse's performance being altered after the administration of prohibited substances, including approved drugs used for legitimate treatment. Veterinarians have to advise owners or trainers on appropriate withholding times to guarantee that their horses may safely compete after drug administration. In order to propose tailored withdrawal times, several horse organisations released detection time (DT) values, for the main veterinary drugs used in horses. One of the possible limits to the information provided by published DTs in horses is the ...
Jedziniak P, Szprengier-Juszkiewicz T, Olejnik M, Zmudzki J.A confirmatory method for the determination of residues of nine non-steroidal anti-inflammatory drugs and one metabolite in animal muscles has been developed. After enzymatic hydrolysis samples were extracted with acetonitrile and cleaned up using alumina and C(18) SPE cartridges. Liquid chromatography-tandem mass spectrometry was used for the separation and determination of analytes. The method was validated in bovine muscles, according to the Commission Decision 2002/657/EC criteria. Applicability of the method in the analysis of swine, horse and chicken muscles was checked by precision and ...
Lotfollahzadeh S, Mokhber-Dezfouli MR, Tajik P, Bokaie S, Watson DG.The present survey evaluated the use of prohibited substances cases in the first 2 years of medication regulation in horseracing in Iran so that the impact of these regulations on the level of positive cases over the period could be assessed. Objective: To determine the prevalence of positive tests for prohibited substances in horse races during 2 years of a drugs testing programme in Iran. Methods: A total of 656 horses that were winners or second in races were tested during the 2 year study. In the first year 354 horses (209 males and 145 females) and in the second year 302 horses (155 males...
Andrews FM, Reinemeyer CR, Longhofer SL.Eighteen mature, healthy horses were divided into three groups (six per group) receiving either no treatment, 15 consecutive days of phenylbutazone (PBZ), or 15 consecutive days of suxibuzone (SBZ) at recommended label doses. Horses underwent endoscopy before and after the treatment period and were assigned gastric ulcer scores. Gastric ulcer number and severity scores were similar across treatment groups. These findings suggest that when administered at the recommended label dose for 15 days, neither PBZ nor SBZ causes an increase in the number or severity of gastric ulcers over what would be...
Schoonover MJ, Jann HW, Blaik MA.To quantitatively compare 3 commonly used treatments for navicular syndrome (NS) in horses: heel-elevation shoeing alone, heel-elevation shoeing and phenylbutazone administration, heel-elevation shoeing and injection of the distal interphalangeal joint (DIPJ) with triamcinolone acetonide (TA), and all 3 treatments in combination. Methods: 12 horses with NS. Methods: A force plate was used to measure baseline peak vertical ground reaction force (PVGRF) of the forelimbs. Each horse's forelimbs were shod with 3 degrees heel-elevation horseshoes; PVGRF was measured 24 hours and 14 days after shoei...
Knych HK, Arthur RM, McKemie DS, Seminoff K, Hamamoto-Hardman B, Kass PH.Phenylbutazone (PBZ) is a potent mon-steroidal anti-inflammatory drug used commonly in performance horses. The objectives of the current study were to describe blood and urine concentrations and the pharmacokinetics of PBZ and its metabolites following intravenous (IV) and oral administration and to describe the duration of pharmacodynamic effect. To that end, 17 horses received an IV administration and 18 horses an oral administration of 2 g of PBZ. Blood and urine samples were collected prior to and for up to 96Â hours post drug administration. Whole blood samples were collected at various t...
Meschter CL, Gilbert M, Krook L, Maylin G, Corradino R.Phenylbutazone, a nonsteroidal anti-inflammatory drug known to produce gastric ulcers, was administered intravenously (13.46 mg/kg body weight) daily to 12 horses. Horses were euthanatized daily after 24, 48, 72, and 96 hours following the initial injection. Eight untreated horses served as controls. Small multifocal pyloric erosions were seen after 24 hours and then progressed in severity over time. The erosions were characterized by sloughing of the surface epithelium, subepithelial bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries, and micro...
Keegan KG, Messer NT, Reed SK, Wilson DA, Kramer J.To determine the effectiveness of administering multiple doses of phenylbutazone alone or a combination of phenylbutazone and flunixin meglumine to alleviate lameness in horses. Methods: 29 adult horses with naturally occurring forelimb and hind limb lameness. Methods: Lameness evaluations were performed by use of kinematic evaluation while horses were trotting on a treadmill. Lameness evaluations were performed before and 12 hours after administration of 2 nonsteroidal anti-inflammatory drug (NSAID) treatment regimens. Phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, ever...
Cohen ND, Carter GK, Mealey RH, Taylor TS.Right dorsal colitis in horses has been associated with administration of phenylbutazone. Although reports of right dorsal colitis in this species have described surgical treatment associated with a poor prognosis, we have had success treating this condition medically. This report describes 5 horses with right dorsal colitis confirmed during celiotomy that were initially managed medically. All horses had a history of intermittent abdominal pain; weight loss was noted in only 1 horse. The doses (2.0 to 4.6 mg/kg PO bid) and duration (5 to 30 days) of administration of phenylbutazone were not un...
Reed SK, Messer NT, Tessman RK, Keegan KG.To assess effects of treatment with phenylbutazone (PBZ) or a combination of PBZ and flunixin meglumine in horses. Methods: 24 adult horses. Methods: 13 horses received nonsteroidal antiinflammatory drugs (NSAIDs) in a crossover design. Eleven control horses were exposed to similar environmental conditions. Treated horses received PBZ (2.2 mg/kg, PO, q 12 h, for 5 days) and a combination of PBZ and flunixin meglumine (PBZ, 2.2 mg/kg, PO, q 12 h, for 5 days; flunixin meglumine, 1.1 mg/kg, IV, q 12 h, for 5 days). Serum samples were obtained on day 0 (first day of treatment) and day 5, and total...
Clark JO, Clark TP.Critical to reducing patient morbidity as well as heightened ethical awareness, alleviation of pain in animals has become integral to medical case management and surgical procedures. Pharmacotherapy is directed at peripheral nociceptors, primary and secondary spinal neurons, and pain-processing areas in the CNS. Accordingly, three primary pharmacologic strategies have evolved: drugs that bind to and activate opioid receptors, drugs that bind to and activate alpha 2 receptors, and drugs that reduce de novo prostaglandin synthesis. In horses, the two predominant types of pain encountered are mus...
Morris DD, Garcia M.Adult horses showed a mild diurnal variation in equine plasma thyroxine (T4) concentrations, but not triiodothyronine (T3). Plasma T4 concentrations tended to be higher between 5 PM and 8 PM than at 8 AM. Increases in plasma T4 and T3 were similar in adult healthy horses given 5, 10, or 20 IU of thyroid-stimulating hormone (TSH). The T4 peaked at approximately twice (2.0 +/- 0.4 times) as high as the base line at 6 to 12 hours after the TSH was given. The greatest change from base line T3 occurred at 1 to 3 hours after the TSH was given, but the magnitude of increase was widely variable (4.36 ...
Slauson DO, Skrabalak DS, Neilsen NR, Zwahlen RD.Equine neutrophils (PMN) were isolated from citrated normal blood by density gradient separation on Ficoll-Hypaque to greater than 96% purity and 98% viability and an average of 3.78 x 10(7) PMN/ml. The agonist C5a des Arg was used in serial dilutions of whole zymosan-activated equine plasma (ZAP) or was partially purified from ZAP by column chromatography. Purified equine PMN exhibited rapid aggregation following incubation with C5a des Arg which was further dependent on the availability of divalent cations, especially Mg++. The microfilament disruptive agent cytochalasin B (5 micrograms/50 m...
Ricord M, Andrews FM, Yñiguez FJM, Keowen M, Garza F, Paul L, Chapman A, Banse HE.Phenylbutazone is commonly prescribed for treatment of various painful or inflammatory disorders in horses, but is associated with gastrointestinal (GI) adverse effects. Anecdotally, many practitioners prescribe omeprazole concurrently with phenylbutazone to reduce development of equine gastric ulcer syndrome (EGUS), but the efficacy and safety of this practice remains unknown. Objective: To evaluate the effect of omeprazole on phenylbutazone-induced equine glandular gastric disease (EGGD) and equine squamous gastric disease (ESGD). Methods: Randomised block experimental design. Methods: Twent...
Maitho TE, Lees P, Taylor JB.The disposition of phenylbutazone (4.4 mg/kg), administered intravenously to six Welsh Mountain ponies, was described by a two-compartment open model. Pharmacokinetic parameters were not significantly different after morning dosing in comparison with afternoon dosing. When phenylbutazone (4.4 mg/kg) was administered orally to the same ponies, marked variations in time to peak concentrations were produced with different feeding schedules. When access to hay was permitted before and after dosing, the mean time to peak concentration was 13.2 +/- 1.2 h and double peaks in the plasma concentration-...
Johnstone IB.Nonsteroidal anti-inflammatory drugs are commonly used in the treatment of inflammatory conditions, and have potential value in the treatment of thrombotic disease in the horse. This study compares the potency of three nonsteroidal anti-inflammatory drugs phenylbutazone, naproxen (equiproxen) and flunixin meglumine (banamine) with respect to their effects on equine platelets. Two functional responses of horse platelets were evaluated in vitro: their ability to aggregate and their ability to make available platelet factor 3 procoagulant activity. Flunixin at a concentration of 10(-6) M signific...
Beluche LA, Bertone AL, Anderson DE, Rohde C.To evaluate the effects of orally administered phenylbutazone on proteoglycan synthesis and chondrocyte inhibition by IL-1beta in articular cartilage explants of horses. Methods: 11 healthy 1- to 2-year-old horses. Methods: Horses were randomly assigned to the control (n = 5) or treated group (4.4 mg of phenylbutazone/kg of body weight, p.o., q 12 h; n = 6). Articular cartilage specimens were collected before treatment was initiated (day 0), after 14 days of treatment, and 2 weeks after cessation of treatment (day 30). Proteoglycan synthesis and stromelysin concentration in cartilage extracts ...
Panjehshahin MR, Yates MS, Bowmer CJ.The fluorescent probes warfarin and dansylsarcosine are known to selectively interact with binding sites I and II, respectively, on human albumin. This paper investigates whether similar binding sites exist on bovine, dog, horse, sheep and rat albumins. Binding sites on albumins were studied by: (1) displacement of warfarin and dansylsarcosine by site I (phenylbutazone) and site II (diazepam) selective ligands; (2) the effects of non-esterified fatty acids (carbon chain lengths: C5-C20) and changes in pH (6-9) on the fluorescence of warfarin and dansylsarcosine; and (3) the ability of site sel...
Meschter CL, Gilbert M, Krook L, Maylin G, Corradino R.Phenylbutazone, a non-steroidal anti-inflammatory drug known to produce intestinal erosions, was administered intravenously (13.46 mg/kg bodyweight) to 12 horses which were killed after 24, 48, 72 and 96 h. Eight untreated horses served as controls. Annular erosions in the duodenum and mucosal necrosis in the colon were seen after 48 h which progressed in severity. The erosions were characterised by sloughing of the surface epithelium, subepithelial cleft and bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries and microthrombosis. Large numbers o...
Wohlfender FD, Doherr MG, Driessen B, Hartnack S, Johnston GM, Bettschart-Wolfensberger R.Multicentre Confidential Enquiries into Perioperative Equine Fatalities (CEPEF) have not been conducted since the initial CEPEF Phases 1-3, 20 years ago. Objective: To collect data on current practice in equine anaesthesia and to recruit participants for CEPEF-4. Methods: Online questionnaire survey. Methods: An online questionnaire was prepared and the link distributed internationally to veterinarians possibly performing equine anaesthesia, using emails, posters, flyers and an editorial. The questionnaire included 52 closed, semiclosed and open questions divided into 8 subgroups: demographic ...
Valk N, Doherty TJ, Blackford JT, Abraha TW, Frazier DL.The effect of phenylbutazone on gastric emptying in horses was determined by measuring serum concentrations of acetaminophen. Gastric emptying was determined in normal fasted horses (n = 6), horses given endotoxin intravenously (n = 6), horses given intravenous phenylbutazone (n = 6), and horses given intravenous phenylbutazone plus endotoxin (n = 6). The mean time to reach maximum serum acetaminophen concentration (Tmax), the maximum serum concentration (Cmax), and the area under the serum acetaminophen concentration versus time curve (AUC) were compared among treatment groups. Phenylbutazone...
Toutain PL, Lassourd V, Costes G, Alvinerie M, Bret L, Lefebvre HP, Braun JP.The present study was undertaken to measure the weight of muscle destroyed by an intramuscular injection of phenylbutazone (PBZ) in horses. In six horses, CK disposition parameters were evaluated after intravenous (i.v.) and intramuscular (i.m.) administration of a CK horse preparation. The same horses received PBZ, a potentially irritating agent, by i.v. and i.m. (neck and hindquarter) routes. Data were analysed using compartmental approaches and instantaneous CK flux was calculated using a discrete deconvolution method. For a 150 U/kg CK dose, the steady-state volume of distribution was 0.05...
Knych HK, Arthur RM, McKemie DS, Baden RW, Seminoff K, Kass PH.Flunixin meglumine (FM) and phenylbutazone (PBZ) are potent anti-inflammatory agents and as such their potential to mask injuries that would otherwise keep a horse from training or racing is concerning. A common practice in racetrack medicine in the USA is to administer the two drugs within close proximity (24Â hours apart) of each other, raising the concern of pharmacokinetic interactions and enhanced anti-inflammatory effects. Objective: Describe the pharmacokinetics and effects of PBZ on the clearance of FM when administered in close proximity as well as effects on inflammatory mediators. M...
Waran N, Williams VM, Clarke N, Bridge IS.To explore attitudes towards and use of analgesia in horses by veterinarians in New Zealand. Methods: A postal questionnaire was sent out to 457 veterinarians identified as working with horses in New Zealand. Questions covered demographics and practice data; analgesic drugs available for use and used in practice; analgesic management of specific conditions including assessment of pain, drugs used, and frequency of cases; factors influencing the choice and use of analgesic agents; and attitudes and personal experience. Results: Ninety-seven questionnaires containing useable data were received, ...
Whitfield-Cargile CM, Coleman MC, Cohen ND, Chamoun-Emanuelli AM, DeSolis CN, Tetrault T, Sowinski R, Bradbery A, Much M.Gastrointestinal (GI) injury and dysbiosis are adverse events associated with nonsteroidal anti-inflammatory drug (NSAID) use in horses. Phenylbutazone has been shown to alter GI barrier function both in vitro and ex vivo, but its effects on barrier function have not been assessed in vivo. In addition, the ability of nutritional therapeutics to prevent these changes is not known. Objective: Our objectives were to determine whether (a) phenylbutazone affected barrier function in vivo and (b) if phenylbutazone-induced GI injury could be ameliorated by the use of a nutritional therapeutic. Method...
Mercer MA, McKenzie HC, Byron CR, Pleasant RS, Bogers SH, Council-Troche RM, Werre SR, Burns T, Davis JL.Acetaminophen has been used clinically in horses alone or combined with traditional non-steroidal anti-inflammatory drugs for treatment of musculoskeletal pain in horses. Objective: To determine the pharmacokinetics and efficacy of acetaminophen at two doses in horses with mechanically induced lameness compared with phenylbutazone or placebo control. Methods: In vivo experiment. Methods: Nine healthy mares with mechanical lameness induced via a reversible sole pressure horseshoe model were treated with acetaminophen (20 mg/kg PO; A20), acetaminophen (30 mg/kg PO; A30), phenylbutazone (2.2â...
Squire KR, Adams SB, Widmer WR, Coatney RW, Habig C.A 5-year-old Arabian stallion with moderate effusion in the right carpal canal and intermittent lameness in this limb was diagnosed to have an osteochondroma projecting from the distal portion of the radius into the carpal canal. oral phenylbutazone treatment over the next 3 years allowed the stallion to continue its show career. Right forelimb lameness returned at that time, and ultrasonography revealed the osteochondroma impinging on the dorsal surface of the deep digital flexor tendon. The owner elected to have the osteochondroma surgically removed. The horse was anesthetized, and the carpa...
Hu HH, MacAllister CG, Payton ME, Erkert RS.To compare analgesic effects of phenylbutazone administered at a dosage of 4.4 mg/kg/d (2 mg/lb/d) or 8.8 mg/kg/d (4 mg/lb/d) in horses with chronic lameness. Methods: Controlled crossover study. Animals-9 horses with chronic forelimb lameness. Methods: Horses were treated i.v. with phenylbutazone (4.4 mg/kg/d or 8.8 mg/kg/d) or saline (0.9% NaCl) solution once daily for 4 days. All horses received all 3 treatments with a minimum of 14 days between treatments. Mean peak vertical force (mPVF) was measured and clinical lameness scores were assigned before initiation of each treatment and 6, 12, ...
Sanz MG, Sellon DC, Cary JA, Hines MT, Farnsworth KD.To compare the analgesic efficacy of administration of butorphanol tartrate, phenylbutazone, or both drugs in combination in colts undergoing routine castration. Methods: Randomized controlled clinical trial. Methods: 36 client-owned colts. Methods: Horses received treatment with butorphanol alone (0.05 mg/kg [0.023 mg/lb], IM, prior to surgery and then q 4 h for 24 hours), phenylbutazone alone (4.4 mg/kg [2.0 mg/lb], IV, prior to surgery and then 2.2 mg/kg [1.0 mg/lb], PO, q 12 h for 3 days), or butorphanol and phenylbutazone at the aforementioned dosages (12 horses/group). For single-drug-tr...
Zambruno T, Georgopoulos SP, Boden LA, Parkin TDH.To examine the association between prerace administration of phenylbutazone and the risk of musculoskeletal injury (MSI) and fatal injury in Thoroughbred racehorses that raced between 2006 and 2015 at 2 of the 4 official racetracks in Argentina. Methods: Data from racetrack databases and veterinary reports on 283,193 race starts. Methods: Data were collected relating to race performance and injury outcomes for starts at these tracks. The incidence of MSI and fatal injury was calculated for each year, stratified by the declared prerace administration of phenylbutazone. Univariable logistic regr...
King JN, Gerring EL.Post operative ileus is a serious complication of abdominal surgery in horses and there is evidence that endotoxin plays a significant role in its pathogenesis. Pre-treatment with intravenous (i.v.) flunixin (1.1 mg/kg bodyweight [bwt]) or phenylbutazone (4.4 mg/kg bwt) significantly antagonised the acute disruption of gastric, small intestinal and large intestinal motility induced by 0.1 microgram/kg bwt i.v. endotoxin in ponies implanted with gastrointestinal strain gauges. Phenylbutazone was more effective than flunixin and this was significant (P < 0.01) for the stomach and left dorsal col...
Turner TA.Navicular disease was diagnosed in 36 horses. Each horse was treated, using shoeing as the only major means of treatment. Phenylbutazone was used initially for 10 days after shoeing. Shoeing was designed to correct preexisting problems, enhance physiologic function of the foot, and ease breakover of the foot. The horses were evaluated over a period ranging from 12 to 54 months. The lameness improved in all horses. Thirty-one of the 36 horses treated were not lame when last evaluated. Shoeing was most effective when performed within 8 months of the first signs of lameness. Also, horses used for...
