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There is no specific antidote for ivermectin toxicity. Treatment involves decontamination including multiple doses of activated charcoal (Table 4.1) to interrupt the enterohepatic recirculation of ivermectin; a saline cathartic (Table 4.1), supportive care (intravenous fluids, ventilator support, cardiovascular, respiratory and neurologic monitoring, nursing care), AEMs (see Table 4.1 and Chapters 12 and 24) and myorelaxants in animals with tremors. Induction of emesis (Table 4.1) can be considered in animals with no neurologic signs and recent oral exposure. Historically, GABA agonists AEMs (such as benzodiazepines and barbiturates) were not recommended in animals with ivermectin-induced seizures as ivermectin is also a GABA agonist and exacerbation of clinical signs was a concern. However, this no longer seems to be the case. AEMs with a different mode of action such as levetiracetam (see Table 4.1 and Chapter 16) may be used.

Intravenous lipid emulsion (IVLE) administration has been suggested as a treatment that may shorten the duration of clinical signs of macrocyclic lactones and other lipophilic compound toxicosis. It is hypothesized that the IVLE acts as a ‘lipid sink’ and draws lipophilic compounds into the plasma lipid phase, thereby removing the compound from the target tissues and promoting its elimination (Merola and Eubig, 2012). Intralipid 20% preparation for intravenous infusion administered at 1.5 ml/kg as initial slow bolus followed by a constant rate infusion of 0.25 ml/kg/min over a 30–60 min period has been reported to result in rapid recovery in dogs and one cat with ivermectin toxicosis (Pritchard, 2010; Clarke et al., 2011; Bates et al., 2013; Epstein and Hollingsworth, 2013). IVLE does not seem beneficial to dogs that are homozygus for the ABCB1-1Δ mutation, possibly because of pre-existent high brain tissue concentration of ivermectin (Wright et al., 2011). Physostig-mine and flumazenil may also be beneficial in the treatment of ivermectin toxicity. In severely affected animals intensive nursing care including respiratory, cardiovascular and nutritional support are necessary for several days.