Description    Horses given multiples of the recommended doses of the antiparastic drugs ivermectin or moxidectin developed signs of toxicity, and in rare instances clinical signs were associated with the recommended dose. Administration of moxidectin to foals younger than 4-months has been associated with severe toxicosis, coma, and death.
Species   Equine
Signs   Abnormal proprioceptive positioning, Abnormal pupillary response to light, Abnormal upper airway breathing sounds, Anorexia, Arrhythmia, Ataxia, Blindness, Cold skin, Coma, Cyanosis, Decreased respiratory rate, Dehydration, Disoriented, Dryness oral mucosa, Dullness, Dysmetria, Dysphagia, Dyspnea, Enlarged, distended, urinary bladder, Excessive salivation, Excitement, Fever, Forelimb weakness, Generalized weakness, Head pressing, Head, face, ears, jaw weakness, droop, Hyperesthesia, Hypothermia, Inability to stand, Increased respiratory rate, Mydriasis, Nystagmus, Oliguria or anuria, Pale, Paraparesis, Prolonged capillary refill time, Seizures or syncope, Skin edema, Sudden death, Tachycardia, Tetraparesis, Tongue weakness, Trembling, Tremor, Urinary incontinence, Ventricular premature beat, Weak pulse
References   Norman TE. Concurrent Ivermectin and Solanum spp. Toxicosis in a Herd of Horses. J Vet Intern Med 2012;26:1439 [Web Reference]
Bruenisholz H. Treatment of Ivermectin Overdose in a Miniature Shetland Pony Using Intravenous Administration of a Lipid Emulsion. J Vet Intern Med 2012;26:407 [Web Reference]
Dawson DR. Toxins and Adverse Drug Reactions Affecting the Equine Nervous System. Vet Clin North Am Equine Pract 2011;27:507 [Web Reference]
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