Topic:Adverse Effects
Adverse effects in horses refer to unintended and potentially harmful outcomes that occur as a result of medical treatment, environmental exposure, or other interventions. These effects can impact various physiological systems and may manifest as behavioral changes, organ dysfunction, or other health-related issues. Monitoring and understanding adverse effects are important for ensuring the safety and well-being of horses, particularly in the context of veterinary medicine and equine management. This page gathers peer-reviewed research studies and scholarly articles that explore the causes, mechanisms, and implications of adverse effects in horses, offering insights into their identification, management, and prevention.
Use of Liposomal Gentamicin for Treatment of 5 Foals with Experimentally Induced Rhodococcus equi Pneumonia. Adverse effects of, and bacterial resistance to, macrolides used to treat Rhodococcus equi infections have prompted search for clinically effective alternative antimicrobials. Liposomal gentamicin (LG) is effective against R. equi in vitro and decreases tissue concentrations of R. equi in experimentally infected mice. Effectiveness of LG treatment of foals with R. equi pneumonia, however, has not been described. Objective: Liposomal gentamicin is safe and effective for treating foals with R. equi pneumonia. Methods: Ten foals with experimentally induced R. equi pneumonia. Methods: Pilot treatm...
Extrapyramidal system neurotoxicity: animal models. The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This cha...
Rhabdomyolysis Secondary to Clenbuterol Use and Exercise. The literature regarding rhabdomyolysis secondary to illicit drug use is sparse. Clenbuterol is a bronchodilator approved for veterinary use, which in high doses can increase protein deposition and lipolysis similarly to anabolic steroids, and is thereby abused for bodybuilding and weight loss effects. Clenbuterol has previously been described in case reports to be cardiotoxic, with patient presentations similar to overdoses of sympathomimetic substances, but reports of rhabdomyolysis are limited to a single case series in horses. Methods: We report the first case of rhabdomyolysis secondary t...
Pharmacokinetics of ketorolac tromethamine in horses after intravenous, intramuscular, and oral single-dose administration. Nonsteroidal anti-inflammatory drugs (NSAIDs) are an integral component of equine analgesia, yet currently available NSAIDs are both limited in their analgesic efficacy and have adverse effects. The NSAID ketorolac tromethamine (KT) is widely used in humans as a potent morphine-sparing analgesic drug but has not been fully evaluated in horses. The purpose of this study was to determine the pharmacokinetic profile of KT in horses after intravenous (i.v.), intramuscular (i.m.), and oral (p.o.) administration. Nine healthy adult horses received a single 0.5-mg/kg dose of KT via each route of admi...
Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015. Triamcinolone is commonly used in equine practice for the treatment of orthopaedic conditions. A serious potential adverse effect of triamcinolone is laminitis. However, evidence for the risk of laminitis associated with triamcinolone use is limited. Objective: To determine the risk of laminitis within 90 days of triamcinolone administration and compare with the risk of laminitis in a veterinary-attended horse population. Methods: Retrospective study of clinical records. Methods: Text mining and data extraction was performed using content analysis software (SimStat-WordStat v.6) on a database ...
Macrolide-induced hyperthermia in foals: Role of impaired sweat responses. The mechanism of hyperthermia, a potentially fatal adverse effect of erythromycin treatment of foals, is unknown. Objective: To determine the cause of erythromycin-associated hyperthermia. It was hypothesised that the normal sweat response of foals is impaired by treatment with erythromycin. Methods: Blinded, crossover study in 10 healthy pony foals. Methods: Foals kept in stalls were given either erythromycin (25 mg/kg bwt orally, 3 times daily) or control for 10 days then turned out for a further 10 days. Quantitative intradermal terbutaline sweat tests were performed on Days 1 (baseline)...
Pharmacokinetics and disposition of flupirtine in the horse. Flupirtine (FLU) is a non-opioid analgesic drug, with no antipyretic or anti-inflammatory effects, used in the treatment of a wide range of pain states in human beings. It does not induce the side effects associated with the classical drugs used as pain relievers. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy horses. Six mixed breed adult mares were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received ...
Does Clinical Treatment with Phenylbutazone and Meloxicam in the Pre-ovulatory Period Influence the Ovulation Rate in Mares? The presence of anovulatory haemorrhagic follicles during the oestrous cycle of mares causes financial impacts, slowing conception and increasing the number of services per pregnancy. Non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam and phenylbutazone are used in the treatment of several disorders in mares, and these drugs can impair the formation of prostaglandins (PGs) and consequently interfere with reproductive activity. This study aimed to evaluate the effects of treatment with NSAIDs on the development of pre-ovulatory follicles in mares. In total, 11 mares were studied o...
A randomized controlled field trial of a novel trimethoprim-sulfadiazine oral suspension for treatment of Streptococcus equi subsp zooepidemicus infection of the lower respiratory tract in horses. To evaluate the effectiveness of a novel trimethoprim-sulfadiazine oral suspension for the treatment of naturally acquired Streptococcus equi subsp zooepidemicus infection in horses. Methods: Randomized, controlled field trial. Methods: 180 horses with S equi subsp zooepidemicus infection. Methods: Horses with lower respiratory tract infections caused by S equi subsp zooepidemicus were treated with a new formulation of combined trimethoprim-sulfadiazine oral suspension at a dosage of 24 mg/kg (10.9 mg/lb) twice daily for 10 days (treatment group) or with an equivalent volume of saline (0.9% Na...
Strangles in horses can be caused by vaccination with Pinnacle I. N. The differentiation of live attenuated vaccine strains from their progenitor and wild-type counterparts is important for ongoing surveillance of product safety and improved guidelines on their use. We utilised a genome sequencing approach to confirm that two cases of strangles in previously healthy horses that had received the Pinnacle I. N. vaccine (Zoetis) were caused by the vaccine strain. Our data shed new light on the safety of this vaccine and suggest that factors beyond the maturity of the animal's immune system influence the development of adverse reactions.
Cardiovascular effects of pimobendan in healthy mature horses. Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. Objective: To determine the cardiovascular effects of pimobendan in healthy mature horses. Methods: Randomised experimental study. Methods: Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses ...
Tiludronate concentrations and cytologic findings in synovial fluid after intravenous regional limb perfusion with tiludronate in horses. Anecdotal accounts of tiludronate administration via intravenous regional limb perfusion (IVRLP) exist despite a lack of information regarding safety for synovial structures in the perfused area. The objective of this study was to determine whether tiludronate concentrations in synovial structures after IVRLP with low dose (0.5 mg, LDT) or high dose (50 mg, HDT) tiludronate remain below a value demonstrated in vitro to be safe for articular cartilage (<19,000 ng/ml), and to determine effects of tiludronate on synovial fluid cytology variables compared to saline perfused control limbs. Using...
Evaluation of a thyrotropin-releasing hormone solution stored at room temperature for pituitary pars intermedia dysfunction testing in horses. To determine whether plasma ACTH concentrations vary following administration of a thyrotropin-releasing hormone (TRH) solution prepared for research purposes and stored at -20°C (rTRH) or prepared by a compounding pharmacy and stored at room temperature (approx 22°C; cTRH). Methods: 34 adult horses. Methods: The study consisted of 2 experiments. In experiment 1, each horse underwent 2 TRH stimulation tests separated by 24 hours; 10 horses were administered cTRH for the first test and rTRH for the second test (group 1), 10 horses were administered rTRH for the first test and cTRH for the sec...
Effect of a probiotic on prevention of diarrhea and Clostridium difficile and Clostridium perfringens shedding in foals. Up to 60% of foals develop diarrhea within 6 months after birth. Preventive measures are limited but potentially probiotics could be used. Objective: To evaluate the effect of a newly designed probiotic on the incidence of foal diarrhea in a randomized field trial. Methods: Seventy-two healthy neonatal foals. Methods: Randomized, placebo-controlled field trial. Foals were administered a placebo or probiotic for 3 weeks and monitored for an additional week. A total of 3 fecal samples were taken from each foal at biweekly intervals. Statistical modeling was applied for comparison of incidence an...
An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24 months follow-up. Polyacrylamide hydrogel (PAAG) was evaluated recently to treat osteoarthritis (OA) in horses with highly encouraging results; however no long term field-study was done to explore its clinical efficacy and lasting effect. The objective of this study was to evaluate the efficacy of PAAG in improving clinical signs of OA in horses. We hypothesized that lameness grade would significantly improve and the effect would last at least 2 years in osteoarthritic joints treated with PAAG. Forty three horses older than 2 years with OA in only one joint based on clinical evaluation, intra-articular anaesthe...
Adverse reactions in horses that underwent general anesthesia and cervical myelography. The study was prompted by a perceived high prevalence of myelographic complications varying in severity and type, and attributed to the contrast material or the procedure. Objective: 1. Any adverse reaction (AAR) is associated with a change in CSF volume induced either by removal of CSF or addition of contrast material. 2. AAR occurs more frequently in horses with higher premyelography neurologic grade. 3. Nonspecific hyperthermia is attenuated by anti-inflammatory and osmotic agents. Methods: Horses (n = 278) that underwent myelography between 2000 and 2012 at 5 institutions: A (87), B (68), ...
Anthrax vaccine associated deaths in miniature horses. During a widespread anthrax outbreak in Canada, miniature horses were vaccinated using a live spore anthrax vaccine. Several of these horses died from an apparent immune-mediated vasculitis temporally associated with this vaccination. During the course of the outbreak, other miniature horses from different regions with a similar vaccination history, clinical signs, and necropsy findings were found. Vaccin contre l’anthrax associé à la mort de chevaux miniatures. Durant une vaste éclosion d’anthrax au Canada, des chevaux miniatures ont été vaccinés en utilisant un vaccin à base de sp...
Intraarterial Injection of Iodinated Contrast Medium for Contrast-Enhanced Computed Tomography of the Equine Head. Minimizing the volume of contrast administered for contrast-enhanced computed tomography (CT) of the equine head is desirable for reducing costs and risks of adverse reactions, however evidence-based studies on the effects of varying volumes on image quality are currently lacking. The objective of the current study was to determine whether low-volume intraarterial administration of contrast medium would result in an equivalent image quality and tissue attenuation vs. high-volume intravenous bolus administration. A prospective cross-over experimental design was used in a sample of six horses. A...
Efficacy and safety of lomefloxacin on bacterial extraocular disease in the horse. Lomefloxacin is a broad-spectrum fluoroquinolone antibiotic used for the treatment of bacterial extraocular disease. This study investigated the efficacy and safety of lomefloxacin eye drops for bacterial extraocular disease in horses. Lomefloxacin ophthalmic solution (0.3%) was instilled three times daily for 2-5 days in 65 horses diagnosed with bacterial extraocular disease based on clinical findings. Clinical observations and bacteriological examinations were performed at the start of treatment, 2 and 5 days after the start of treatment, and at the discontinuation or termination of treatmen...
Efficacy of gamithromycin for the treatment of foals with mild to moderate bronchopneumonia. Gamithromycin is active in vitro against the bacterial agents most commonly associated with bronchopneumonia in older foals. However, the clinical efficacy and safety of this drug have not been investigated. Objective: Gamithromycin is effective for the treatment of bronchopneumonia in foals. Methods: One hundred and twenty-one foals on a farm endemic for infections caused by Rhodococcus equi. Methods: In a controlled, randomized, and double blinded clinical trial, foals with ultrasonographic evidence of pulmonary abscesses (abscess score 8.0-20 cm) were randomly allocated in 3 treatment group...
Vaccination with a live multi-gene deletion strain protects horses against virulent challenge with Streptococcus equi. Strangles, caused by Streptococcus equi subspecies equi (S. equi) is one of the most frequently diagnosed infectious diseases of horses and there remains a significant need to develop new preventative vaccines. We generated a live vaccine strain of S. equi containing deletions in six genes: sagA, hasA, aroB, pyrC, seM and recA, which was administered to nine Welsh mountain ponies via the intramuscular route. Four vaccinated ponies developed adverse reactions following the first vaccination from which the live vaccine strain was isolated. Two of these ponies were withdrawn from the study and se...
The use of nonsteroidal anti-inflammatory drugs in critically ill horses. To review the physiology of the cyclooxygenase (COX) enzymes with reference to the beneficial effects of nonsteroidal anti-inflammatory drugs (NSAIDs) related to their analgesic and antiendotoxic properties as well as the mechanisms responsible for adverse gastrointestinal, renal, and coagulation effects. Methods: Human and veterinary peer reviewed literature Results: NSAIDs are frequently administered to critically ill horses for their analgesic and anti-inflammatory effects. However, NSAIDs have significant side effects principally on the gastrointestinal mucosa and kidneys. These side effec...
Pharmacokinetics and physiologic effects of alprazolam after a single oral dose in healthy mares. The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04 mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of ...
Sudden death of a horse with supraventricular tachycardia following oral administration of flecainide acetate. To describe a case of supraventricular tachycardia and sudden death in a horse following administration of flecainide acetate. Methods: An 8-year-old Hanoverian warmblood gelding was treated for chronic, naturally occurring, supraventricular tachycardia with digoxin, procainamide hydrochloride, quinidine sulfate, and flecainide acetate. After oral administration of flecainide, polymorphic ventricular tachycardia (torsades de pointes) and ventricular fibrillation developed, leading to cardiovascular collapse and death. Conclusions: Atrial fibrillation is the most commonly diagnosed dysrhythmia ...
Pharmacokinetics and selected pharmacodynamics of cobalt following a single intravenous administration to horses. Cobalt has been used by human athletes due to its purported performance-enhancing effects. It has been suggested that cobalt administration results in enhanced erythropoiesis, secondary to increased circulating erythropoietin (EPO) concentrations leading to improvements in athletic performance. Anecdotal reports of illicit administration of cobalt to horses for its suspected performance enhancing effects have led us to investigate the pharmacokinetics and pharmacodynamic effects of this compound when administered in horses, so as to better regulate its use. In the current study, 18 horses were...
Comparison of midazolam and diazepam as co-induction agents with ketamine for anaesthesia in sedated ponies undergoing field castration. To compare intravenous (IV) midazolam and diazepam administered with ketamine for induction of anaesthesia in ponies, already sedated with detomidine, undergoing field castration. Methods: Prospective, randomised, 'blinded', clinical study. Methods: Twenty Welsh pony yearlings. Methods: After IV injection of detomidine (20 μg kg(-1) ) and phenylbutazone (4.4 mg kg(-1) ) ponies were allocated to receive either IV midazolam (group M) or diazepam (group D) (both 0.06 mg kg(-1) ) with ketamine (2.2 mg kg(-1) ) for induction of anaesthesia. Using simple descriptive scales, quality of sedat...
Allogenic mesenchymal stem cells as a treatment for equine degenerative joint disease: a pilot study. Cell-based therapies, such as treatments with mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) are thought to have beneficial effects on the clinical outcome of orthopedic injuries, but very few animal studies with large sample size are published so far. Therefore, the aim of this study was to assess the safety and report the clinical outcome of allogenic, immature or chondrogenic induced MSCs in combination with PRP for the treatment of degenerative joint disease (DJD) in 165 horses. MSCs and PRP were isolated from a 6-year-old donor horse and transplanted either in their native s...
Immunogenicity of an electron beam inactivated Rhodococcus equi vaccine in neonatal foals. Rhodococcus equi is an important pathogen of foals that causes severe pneumonia. To date, there is no licensed vaccine effective against R. equi pneumonia of foals. The objectives of our study were to develop an electron beam (eBeam) inactivated vaccine against R. equi and evaluate its immunogenicity. A dose of eBeam irradiation that inactivated replication of R. equi while maintaining outer cell wall integrity was identified. Enteral administration of eBeam inactivated R. equi increased interferon-γ production by peripheral blood mononuclear cells in response to stimulation with virulent R. ...
Cardiovascular changes after administration of aerosolized salbutamol in horses: five cases. Prevention and treatment of intraoperative hypoxemia in horses is difficult and both efficacy and safety of therapeutic maneuvers have to be taken into account. Inhaled salbutamol has been suggested as treatment of hypoxia in horses during general anesthesia, due to safety and ease of the technique. The present report describes the occurrence of clinically relevant unwanted cardiovascular effects (i.e. tachycardia and blood pressure modifications) in 5 horses undergoing general anesthesia in dorsal recumbency after salbutamol inhalation. Balanced anesthesia based on inhalation of isoflurane in...