Topic:Medication
The topic of medication in horses encompasses the study and application of pharmaceutical substances used to treat, manage, or prevent diseases and conditions in equine patients. This field involves understanding the pharmacokinetics and pharmacodynamics of various drugs, including their absorption, distribution, metabolism, and excretion in horses. Medications commonly administered to horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, anthelmintics, and sedatives. The appropriate use of these medications is critical for ensuring therapeutic efficacy and minimizing adverse effects. Research in this area focuses on dosage optimization, drug interactions, resistance development, and withdrawal times to ensure both the health of the horse and compliance with regulatory standards. This page aggregates peer-reviewed studies and scholarly articles that explore the pharmacological aspects, clinical applications, and regulatory considerations of equine medications.
Equine self-mutilation syndrome (57 cases). Owners who believed they had a horse with self-mutilating behavior were asked to complete a questionnaire to obtain information on the signalment, clinical history, clinical signs, management, and treatment of the condition. Fifty-two owners of 59 horses responded; 2 cases were omitted because an organic cause was determined. Owners also were asked to complete information for unaffected horses on the same farm. Various breeds were affected, and of the 57 horses, 20 were stallions, 31 were geldings, and 6 were mares. Affected horses tended to develop the condition prior to sexual maturity. Clin...
Drug therapy in the neonatal foal. The neonatal period in foals refers to the first 7 days of postnatal life. The effects of drugs (pharmacologic agents) may be different in neonatal foals, particularly during the first 3 days of postnatal life, from those in older foals and adult horses. The changed drug effects decrease as the physiologic processes that affect absorption, distribution, and elimination (metabolism and excretion) of drugs mature. Dosage regimens should take into account the altered pharmacokinetic profiles of drugs, and because of wide individual variation, the response to therapy should be closely monitored fo...
Humane destruction of horses with a mixture of quinalbarbitone and cinchocaine. One hundred and-two horses requiring to be euthanased for a variety of reasons were killed by the intravenous injection of a mixture of quinalbarbitone sodium (400 mg/ml) and cinchocaine hydrochloride (25 mg/ml). The dose rates used were 1 ml/10, 15, 20 and 30 kg bodyweight, and the time of injection was varied between 5 and 25 seconds. The average time to collapse from the start of the injection was 34 seconds and the average time to clinical death was 230 seconds. Slow injection (particularly of the low dose rates) and premedication with detomidine resulted in a longer time to collapse (medi...
Assessment of drug effects on performance. Few definitive studies have been performed that unequivocally demonstrate the ability of a drug to alter the performance of a horse. Nonetheless, the use of drugs in competing horses is regulated worldwide. Drugs have been categorized according to their abuse potential. However, there is still some confusion over what is meant by the terms "performance" and "drug." In the racing community, performance means speed, and fatigue and pain are among its greatest detractors. Speed is most appropriately measured on the racetrack. There are a multiplicity of internal and external variables that influe...
Sedatives, tranquilizers, and stimulants. Drugs of relevance to equine practice that modify the central nervous system (CNS) can be broadly classified as depressants or stimulants. The pharmacologic mechanisms of action, uses, and side effects of selected CNS depressant and stimulant drugs in horses are reviewed. Knowledge of the way these CNS-modifying drugs may affect performance is limited.
Furosemide, bumetanide, and ethacrynic acid. Furosemide and, less commonly, bumetanide and ethacrynic acid are potent diuretics administered to horses for a variety of reasons, including prophylaxis of exercise-induced pulmonary hemorrhage. These drugs affect urine volume and composition, and furosemide has marked effects on plasma volume and composition and on systemic hemodynamics at rest and during exercise.
Pharmacokinetics of phenylbutazone in neonatal foals. Single doses (2.2 mg/kg of body weight) of phenylbutazone (PBZ) were administered IV to 6 neonatal horses (5 to 17 hours old at time of dosing). Plasma concentrations of PBZ and its metabolite oxyphenbutazone were monitored serially for 120 hours after drug administration. Pharmacokinetic variables were calculated, using 1- and 2-compartment open models. Descriptive equations from the best model for each foal were then used to derive model-independent variables describing PBZ disposition. Median volume of distribution at steady-state was 0.274 L/kg (range, 0.190 to 0.401 L/kg). Median terminal...
[Experiences with long-term intravenous therapy using teflon catheters in 80 horses]. In a retrospective study the tolerance to Teflon coated catheters in long-term intravenous medication was evaluated in 80 horses. Catheters were inserted into the jugular vein and remained there for 3 to 30 days (average 8.6 days). Catheters were flushed using an heparinized solution after each medication administration. The site of catheter placement was evaluated daily for swelling, pain and venous distensibility respectively. Swelling at the site of insertion was noted in 10 horses, a small subcutaneous abscess formation was identified in one horse. Fourteen sonographic evaluations were per...
Use of scintimetry to assess effects of exercise and polysulfated glycosaminoglycan on equine carpal joints with osteochondral defects. Combined blood pool and delayed images produced by use of 99mTc-methylene diphosphonate (99mTcMDP) were evaluated as an objective measurement of the response of equine joints with osteochondral defects to postoperative exercise and intra-articularly administered polysulfated glycosaminoglycan (PSGAG). Osteochondral defects (approx 2.4 x 0.9 cm) were induced arthroscopically in the dorsodistal radial carpal bones of 18 ponies. These ponies were randomized (while balancing for age [range 2 to 15; median, 5.0; mean, 5.1 years]) to 2 treatment groups. Nine ponies were assigned to be exercised, and...
[Pain prevention and pain treatment in small and large domestic animals]. The aim of this article is to emphasize the need for analgesic medication in animals in possibly painful situations, especially in the postoperative period. The two large groups of compounds used as analgesics--the opiates and the nonsteroidal antiinflammatory drugs (NSAIDs)--are described with special reference to their pharmacokinetics, side-effects and toxicity, their mechanism of action, their indications and contraindications. Recommended doses of the different drugs available are given for the dog, the cat, the horse, the swine and the small and large ruminants.
Pharmacokinetic profile of sulphamonomethoxine-trimethoprim in horses after intravenous, intramuscular and oral administration. The pharmacokinetic profile of a sulphamonomethoxine-trimethoprim (SMM-TMP) combination was investigated in five horses. The combination was administered intravenously, intramuscularly and orally at a constant dose of 20 mg SMM plus 4 mg TMP kg-1 bodyweight. Following intravenous administration both drugs dispersed rapidly with distribution half-lives of about 12 minutes for SMM and about 18 minutes for TMP. Elimination half-lives for intravenous, intramuscular and oral administration were closely similar, indicating that elimination was independent of administration route. Bioavailability of ...
Serum concentrations of ormetoprim/sulphadimethoxine in 1-3-day-old foals after a single dose of oral paste combination. Ormetoprim (OMP)/sulphadimethoxine (SDM) combinations
have been used in the treatment of fowl cholera, colibacillosis,
salmonellosis, infectious coryza, and other bacterial infections in
poultry (Mitrovic et al. 1969; Maestrone et al. 1979). The drug
combination has also been used in the treatment of colibacillosis
in neonatal pigs (Brandt and Maestrone 1980) and Pasteurella
pneumonia in cattle (Ames et al. 1987). Serum concentrations and
pharmacokinetics of SDM (Oh-Ishi and Nakajima 1964; Durr et
al. 1980) and OMP/SDM (Brown et al. 1989) after intravenous or
oral administration to ad...
Principles of therapeutics. Topical administration of drugs is the treatment of choice for diseases of the anterior segment. Drug levels attained by this means are usually of short duration, however, necessitating frequent therapy or continuous perfusion if prolonged drug levels are required. A drug-delivery device (collagen shield or contact lens) or subconjunctival injections can be used to augment topical therapy if frequent treatment is not possible. Subconjunctival injections are recommended for drugs that have low solubility and, hence, low corneal penetration. Retrobulbar injections are seldom indicated, except fo...
Parasympathetic influence on the arrhythmogenicity of graded dobutamine infusions in halothane-anesthetized horses. We investigated the influence of parasympathetic tone on the arrhythmogenicity of graded dobutamine infusions in horses anesthetized under clinical conditions. Six horses were used in 9 trials. Two consecutive series of graded dobutamine infusions were given IV; each continuous graded dobutamine infusion was administered for 20 minutes. The dobutamine infusion dosage (5, 10, 15, and 20 micrograms/kg of body weight/min) was increased at 5-minute intervals. Isovolumetric saline solution vehicle (v) or atropine (A; 0.04 mg/kg) was administered IV, or bilateral vagotomy (VG) was performed as a tre...
Regional perfusion of the equine carpus for antibiotic delivery. Regional perfusion of carpal tissues by forced intramedullary administration of fluids was evaluated in 10 horses. Results of subtraction radiography after perfusion with a contrast medium demonstrated that perfusate was delivered to the carpal tissues by the venous system. Perfused India ink was distributed uniformly in the antebrachiocarpal and middle carpal synovial membranes. Histologically, the ink was within the venules of the synovial villi. Immediately after perfusion with gentamicin sulfate (1 g), the gentamicin concentrations in the synovial fluid and synovial membrane of the antebra...
Bioavailability and bioequivalence of veterinary drug dosage forms, with particular reference to horses: an overview. The route of administration and formulation of the dosage form affect the bioavailability (rate and extent of absorption) of a drug and may thereby influence the intensity and duration of the pharmacological effect. Location of injection site may affect the plasma concentration profile of drugs administered as aqueous suspensions or sustained release parenteral preparations (procaine penicillin G). When absorption influences the rate of elimination ('flip-flop' phenomenon), the apparent half-life of the drug will be increased (cefazolin sodium, i.m.; meclofenamic acid, p.o.). Absorption genera...
Effects of WEB 2086, an antagonist to the receptor for platelet-activating factor (PAF), on PAF-induced responses in the horse. Platelet-activating factor (PAF) causes oedema and neutrophil accumulation when injected into the skin of normal horses. PAF is also known to induce aggregation of horse platelets in vitro. The selective PAF receptor antagonist WEB 2086 has now been used to determine whether these effects are mediated by PAF receptor activation. Addition of WEB 2086 to equine platelets in vitro inhibited PAF-induced aggregation in a competitive reversible manner (pA2 = 7.14). Inhibition of in vivo inflammatory responses to PAF occurred after local administration of WEB 2086: wheal formation induced by 0.1 micr...