The aim of this study was to investigate the effects of ivermectin poisoning on the brain and some trials and demonstrate the uses the nikethamide or neostigmine as a new method for treatment of ivermectin poisoning with histopathological study. The most important results obtained are: the lethal dose for ivermectin (LD50%) is 67.37 mg/Kg B.W in rabbits, The toxic dose is 33.7 mg/Kg B.W. in rabbit. The pilot study shows that recommended dose for Nikethamide is 0.07 mg/Kg B.W. in rabbits and recommended dose for Neostigmine is 0.05 mg/Kg B.W. in rabbit. The brain histopathological study of G1 group didn't showed any pathological changes, meanwhile the G2 group showed sever pathological changes characterized by Leukoencephalomalacia and perineural and perivascular edema with sever gliosis (satillatosis), and limited pathological lesions recorded in G3. The G4 showed mild histopathology changes as perivascular edema and inflammatory cell aggregation within blood vessels also astrocyte hypertrophy recorded, the histopathological study of G5 group showed congested blood vessel with sever encephalomalacia, microglia hyperplasia and neuronal chromatolysis and neuronophagia. The lesions in brain were directly related to the type of treatment.
We conclude that neostigmine and Nikethamide have detoxifying activity of ivermectin toxicity each alone but Nikethamide is the most important one and has the best safety margin while the combination of neostigmine and Nikethamide is not safe.