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.
Topical treatment of equine aural plaques with nitric acid and zinc solution. Equine aural plaque caused by equine papilloma viruses is common worldwide and affected horses can show severe clinical signs. Due to its viral aetiology, in some countries affected horses are not allowed to compete. Since lesions persist, showing no spontaneous regression, effective and safe treatment is required. Currently, the only treatment with consistent efficacy is imiquimod. Treatment time is prolonged and adverse effects are common. In humans, papilloma warts are successfully and safely treated with topical nitric-zinc complex solutions inducing a painless caustic effect. Objective: T...
Photodynamic therapy with infracyanine green induces keratocyte depopulation in the normal equine cornea. Use of photodynamic therapy (PDT) for the treatment of immune-mediated keratitis (IMMK) in horses is becoming common. The safety and morphologic impact on the normal equine cornea have not been investigated, and the mechanism of its efficacy is unknown. Objective: To investigate the morphologic effects and safety of in vivo PDT on healthy equine corneas. Methods: In vivo experiment. Methods: Six university-owned horses underwent unilateral corneal PDT with intrastromal infracyanine green (EmunDo®) and photoactivation with an 810 nm diode laser (500 mW for 2.5 min = 75 Joules). Compl...
Pharmacokinetics of Topical Administration of Altrenogest in Mares and Implications for Human Health. Altrenogest is a synthetic progestogen widely used in equine reproductive management. Adverse effects to altrenogest have been reported in people with cutaneous exposure reported as the highest exposure pathway. Despite these reports, there has been no quantitative research to determine the capacity for altrenogest to be absorbed through skin. This study aimed to determine if cutaneous application of oral altrenogest results in systemic absorption in mares and to evaluate the influence of application site. A randomized, two-period, two-treatment crossover study was undertaken in eight mares. M...
Reducing Recurrence in Equine Corneolimbal SCC: Outcomes of Adjunctive Cisplatin Biodegradable Bead Therapy. (1) Context: Squamous cell carcinoma (SCC) is the most prevalent ocular neoplasm in horses, with a reported 45% recurrence rate when managed by surgery alone. (2) Objective: To evaluate the effect of adjunctive cisplatin biodegradable beads (CBBs) on recurrence rates of equine corneolimbal squamous cell carcinoma (SCC) and to document associated adverse effects. (3) Methods: Seventeen cases of histopathologically confirmed corneolimbal SCC in horses were retrospectively identified. Masses were surgically excised by keratectomy and/or conjunctivectomy under general anesthesia, followed by impla...
Canagliflozin: Pharmacokinetics, tolerability and glucose/insulin effects of supratherapeutic doses in healthy horses. Sodium-glucose co-transporter 2 inhibitors like canagliflozin (CFZ) have shown promise in preventing hyperinsulinemia-associated laminitis in horses, but data on pharmacokinetics, tolerability, and controlled studies are limited. This randomized, open-label, placebo-controlled, crossover study evaluated these aspects of CFZ treatment in eight healthy Standardbred mares. Each horse received single supratherapeutic oral doses of CFZ (1.8 mg/kg or 3.6 mg/kg) and placebo, with a two-week washout between treatments. A graded glucose infusion (GGI) was administered post-treatment to evaluate glu...
Injection site abscesses associated with commensal and environmental bacteria following intramuscular vaccination in horses. Five previously healthy horses in Korea, including a 19-year-old mixed-breed gelding, a 16-year-old mixed-breed mare, a 13-year-old Thoroughbred gelding, a 12-year-old Belgian warmblood mare, and a 12-year-old Andalusian mare, developed subcutaneous abscesses in the left neck after receiving intramuscular vaccination without prior skin disinfection. The vaccination used was Equivac® 2 in1, containing toxoid and cell-free extract. Within one week, the horses developed localised swelling and/or abscessation at the injection site. One case involved a ruptured abscess, while the others presente...
Horse antithymocyte globulin test doses and infusion reactions in adults with aplastic anemia: A multicenter retrospective experience. Horse antithymocyte globulin carries a black box warning for life-threatening anaphylactic reactions, and prescribing information recommends test doses to identify patients at highest risk of this adverse effect. The predictive value of such test doses is not well validated, and practicality of use is unclear. Methods: This was a planned secondary analysis of a multicenter, retrospective cohort study in adults with severe aplastic anemia being managed with horse antithymocyte globulin as part of their treatment regimen. Qualitative and quantitative descriptions of test doses and infusion react...
Severe auricular skin necrosis as potential postanaesthetic complication in a horse undergoing general anaesthesia for orthopaedic surgeries. A Trotter mare (aged 5 years 8 months) presented with severe thoracic limb lameness 2 years after screw fixation of a third carpal bone fracture. Septic arthritis of the intermediate carpal joint necessitated three anaesthetics: two arthroscopic lavages in dorsal recumbency, followed by a computed tomography-guided screw explantation with curettage of an infected, sclerotic third carpal bone in right lateral recumbency. For each anaesthetic, maintenance was with isoflurane carried in oxygen and air, and a medetomidine constant rate infusion. Twelve days after the third anaesthetic, the horse h...
Electrochemotherapy with bleomycin for bilateral ocular squamous cell carcinoma in a horse. To describe the procedure and outcome of electrochemotherapy (ECT) with bleomycin as a first-line treatment for bilateral ocular surface squamous neoplasia (OSSN) in the eye of a horse. Methods: A client-owned 5-year-old Haflinger gelding with limbal-conjunctival squamous cell carcinoma. Methods: During general and local anesthesia, injection of bleomycin in the ocular tumor was followed by electroporation, applied with a 15 mm needle electrode, needles held parallel to the ocular surface. Results: Treatment with ECT resulted in therapeutic electric pulses and complete tumor response with no...
[Retrospective study of the effectiveness of human tyrosinase vaccination in eight horses]. Dermal melanoma is a common neoplastic disease in horses, which occurs particularly in gray horses. There are various local and systemic therapeutic approaches to treat this skin tumor. Vaccination with human tyrosinase, ONCEPT ® vaccine, is a newer type of systemic melanoma therapy. In this study, the effectiveness of this ONCEPT ® vaccine was retrospectively examined in eight treated horses. In half of the horses (4) a positive change in tumor growth in the sense of retardation, stagnation and, in one of these horses, even reduction in the size of the melanomas was observed. Of the rem...
Local anaesthetic delivery through indwelling retrobulbar catheters for ocular pain control in horses. Equine corneal disease is common and painful. Current pain mitigation strategies are often suboptimal, especially early in the disease. Objective: To evaluate the effects of local anaesthetic delivery via indwelling retrobulbar catheter on corneal sensitivity, pupil size, pupillary light responses (PLRs), and ocular motility in normal horses. Methods: Randomised, controlled crossover experiment. Methods: One eye was randomly selected from seven horses. A 20-gauge catheter was placed in the retrobulbar space and injected with 10 mL of 0.5% bupivacaine or 0.9% saline. Cochet-Bonnet esthesiomet...
Chemotherapeutics in Equine Practice. Chemotherapy is the treatment of cancerous cells through the use of cytotoxic drugs. Whilst the use of systemic (intravenous) chemotherapy in equine practice is generally limited to the management of lymphoma, cytotoxic drugs are commonly used in the treatment of accessible skin tumors, either by topical application in the form of ointments or injected intralesionally. These drugs should be employed with caution due to the risk of serious adverse effects. In addition, extreme caution should be followed when preparing, handling, administering, and disposing them, due to their carcinogenic, muta...
The Effects of Intra-Articular Triamcinolone and Autologous Protein Solution on Metabolic Parameters in Horses. Intra-articular corticosteroids are a popular treatment choice for joint-associated pain and inflammation in horses despite recent work on the metabolic effects of these drugs. The goal of this project was to compare metabolic effects between intra-articular (IA) triamcinolone acetonide (TA) and an autologous protein solution (APS). Five mixed-breed geldings (4-9 years) were utilized for this project. Three identical and consecutive 28-day treatment blocks were used, with metacarpophalangeal IA treatments consisting of equal volumes of saline, a commercially available APS, or 9 mg of TA. Regul...
Equine Pergolide Toxicity: A Case Series. Veterinary medication exposure may result in human toxicity, with approximately 6,000 exposures to veterinary-only medications reported to poison centers in 2022. There is a paucity of literature on the management of poisoned patients secondary to pharmaceuticals intended for equine use. Pergolide is a dopamine and serotonin receptor agonist and is currently approved to treat equine Cushing's disease. It was previously approved in the United States (US) to treat Parkinson's disease in humans; however, it was withdrawn from the market in 2007 due to its association with valvular heart disease....
Evaluation of pharmacokinetics of metoclopramide administered via subcutaneous bolus and intravenous constant rate infusion to adult horses. To determine the pharmacokinetics (PK) of metoclopramide administered via intravenous continuous rate infusion (IV CRI) and subcutaneous (SC) bolus and evaluate for gastrointestinal motility and adverse side effects. Methods: Experimental study; randomized, crossover design. Methods: Six healthy adult horses. Methods: Each horse received metoclopramide via IV CRI (0.04 mg/kg/h for 24 h) and SC bolus (0.08 mg/kg once), with ≥1 week washout period between. Plasma was analyzed by UPLC-MS/MS. Compartmental modeling was used to determine PK parameters for each treatment; nonparametric sup...
Systemic absorption of triamcinolone acetonide is increased from intrasynovial versus extrasynovial sites and induces hyperglycemia, hyperinsulinemia, and suppression of the hypothalamic-pituitary-adrenal axis. Steroid-associated laminitis remains a major concern with use of corticosteroids in horses. Individual case factors such as joint pathology, pre-existing endocrinopathies, or corticosteroid type, dose, and timing influencing steroid-induced laminitis risk have not been investigated. This study aimed to determine if systemic absorption of triamcinolone acetonide (TA) varies between intrasynovial (antebrachiocarpal) and extrasynovial (sacroiliac) injection sites, and to determine the effects of TA absorption on glucose, insulin, cortisol, and adrenocorticotropic hormone (ACTH). Twenty adult hors...
Comparative efficacy of low-volume retrobulbar anesthesia using three commercial local anesthetics in adult horses. To compare the efficacy of low-volume (5-mL) locoregional retrobulbar anesthesia ("retrobulbar block") by use of 3 commercial local anesthetic formulations. Methods: 8 healthy adult mares. Methods: A block-randomized, masked, controlled design was used. A single ultrasound-guided retrobulbar block was performed with 2% lidocaine, 2% mepivacaine, or 0.5% bupivacaine (n = 5 eyes/group). Contralateral eyes served as untreated controls. End points performed at baseline and time intervals up to 24 hours postblock included the following: assessment of neurophthalmic reflexes/responses, intraocular p...
Comparative study of the bronchodilator efficacy and adverse effects of salbutamol and hyoscine butylbromide in horses with severe asthma. Salbutamol and hyoscine butylbromide (HBB) are commonly used bronchodilators in horses with severe asthma (SA). Objective: To compare the bronchodilation potency, duration, and adverse effects of salbutamol and HBB in SA. Methods: Six horses in exacerbation of SA. Methods: The effects of inhaled salbutamol (1000 μg) and HBB (150 mg, IV) were compared in a randomized, blinded, crossover experiment. Lung function, intestinal borborygmi and heart rate were assessed before and sequentially until 180 minutes after drug administration, and analyzed with 2-way repeated-measures ANOVA and Dunne...
The Management of Xylazine Overdose With Naloxone. This article discusses a rare case of isolated xylazine overdose in a human, treated successfully with naloxone. Xylazine, typically used as a veterinary tranquilizer, acts as a potent α2 adrenergic agonist, leading to sedation, muscle relaxation, and potential respiratory depression. In this case, a female mistakenly injected herself with xylazine mistaking it for a different medication. The report discusses naloxone's role beyond opioid overdose, especially regarding substances causing central nervous system (CNS) depression via mechanisms similar to those of opioids. While naloxone is trad...
Intralesional interferon alpha-2b as a novel treatment for periocular squamous cell carcinoma in horses. To determine the safety and efficacy of perilesional human recombinant interferon alpha-2b (IFNα2b) for treatment of periocular squamous cell carcinoma (PSCC) in horses. Methods: Eleven horses (12 eyes) with PSCC were enrolled in this prospective clinical study with owner consent. Methods: Systemically healthy horses were included in the study following confirmation of PSCC via biopsy. Every two weeks for a maximum of six treatments, horses were sedated and perilesional injection of IFNα2b (10 million IU) was performed. Tumors were measured prior to each injection and at one, three, and 12 m...
The impact of opioid administration on the incidence of postanaesthetic colic in horses. Effective management of postoperative pain is essential to ensure patient welfare, reduce morbidity and optimize recovery. Opioids are effective in managing moderate to severe pain in horses but concerns over their adverse effects on gastrointestinal (GI) motility and associated increased colic risk limit their widespread use. Studies investigating the impact of systemic opioids on both GI motility and colic incidence in horses have yielded inconclusive outcomes. Therefore, this retrospective study aims to assess the influence of systemic administration of butorphanol, morphine, and methadone ...
Equine uveitis: Outcome and adverse effects after one or two intravitreal low-dose gentamicin injections. Uveitis is common in horses, potentially turning chronic (persistent or recurrent) resulting in impaired vision or blindness. All mainstay therapeutics aims at controlling inflammation, but long-term or lifelong treatment is often needed with possibly severe side effects. Therefore, intravitreal injections with low-dose gentamicin (IVGI) have been used in attempt to give a long-lasting result with potentially less side effects. Objective: To retrospectively assess outcome and long-term complications following one or two low-dose IVGI in Swedish horses with chronic uveitis. Methods: Retrospecti...
The impact of the administration of red ginseng (Panax ginseng) on lipid metabolism and free fatty acid profiles in healthy horses using a molecular networking approach. This study investigated the potential benefits of the administration of red ginseng (RG) on lipid metabolism and the profiles of individual free fatty acids (FFAs) in healthy horses. Eight healthy horses, raised under similar conditions, were randomly divided into two groups, each comprising four horses. The experimental group received powdered RG (600 mg/kg/day) mixed with a carrier, and the control group received only the carrier. The parameters associated with lipid metabolism and probable adverse effects were evaluated in both groups after 3 weeks. The computational molecular networkin...
The analgesic effects of magnesium in veterinary patients: a qualitative evidence synthesis. To perform a qualitative evaluation of the analgesic effects of magnesium in domestic animals, including its anaesthetic sparing effects. Methods: All database searches were made using PubMed and Google Scholar. Studies published after 1990, evaluating the use of magnesium and reporting information on analgesia, in dogs, cats, horses, cows, goats and sheep were selected (last search in August 2023). A reference check in the selected papers was performed to identify any study which was omitted. The CERQual (Confidence in Evidence from Reviews of Qualitative research) approach was used to assess...
Use of Autologous Conditioned Serum (ACS) for Osteoarthritis Treatment in Horses: A Systematic Review of Clinical Data. The utilization of Autologous Conditioned Serum (ACS) for treating osteoarthritis (OA) in horses has seen a notable increase in recent years. In vitro studies have consistently identified ACS as a promising therapy for OA joints, contributing to its growing popularity in OA treatment. Despite this, there is a noticeable absence of systematic reviews focused solely on the clinical data of OA patients treated with ACS, excluding the in vitro perspective. This study aims to address this gap by systematically reviewing the latest literature, concentrating solely on clinical data in in vivo studies...
Intravenous loss of over-the-wire catheter guidewires in 13 horses. Over-the-wire (OTW) catheter placement is performed frequently in horses. Intravascular loss of a guidewire has been anecdotally reported, but there is limited information regarding the treatment and outcome of horses that have experienced this complication of OTW catheter placement. Objective: Describe the clinical and diagnostic features, treatment, and outcome of horses experiencing IV guidewire loss at the time of OTW catheter placement. Methods: Thirteen horses. Methods: Multicenter retrospective study to identify horses with IV guidewire loss. Horses of all ages were considered for inclu...
Pharmacokinetics of dexmedetomidine in anaesthetized horses following repeated subcutaneous administration and intravenous constant rate infusion. The inclusion of dexmedetomidine (DEX) within a balanced general anaesthesia protocol is effective in improving the clinical outcome and recovery quality of anaesthesia in horses. This study aimed to determine the pharmacokinetic profile of DEX following repeated subcutaneous (SC) administration at 2 µg/kg every 60 min till the end of the procedure in comparison to intravenous constant rate infusion (CRI) at 1 µg/kg/h in anaesthetized horses undergoing diagnostic procedures up to the end of the diagnostic procedure. Results: In the CRI and SC groups DEX maximum concentrations (Cmax) were ...
A glucagon-like peptide-1 receptor antagonist reduces the insulin response to a glycemic meal in ponies. High plasma concentrations of insulin can cause acute laminitis. Ponies and horses with insulin dysregulation (ID) exhibit marked hyperinsulinemia in response to dietary hydrolyzable carbohydrates. Glucagon-like peptide-1 (GLP-1), an incretin hormone released from the gastrointestinal tract, enhances insulin release, and is increased postprandially in ponies with ID. The aim of this study was to determine whether blocking the GLP-1 receptor reduces the insulin response to a high glycemic meal. Five adult ponies were adapted to a cereal meal and then given two feed challenges 24 h apart of a me...