Milbemycin A3 Oxime is an opener of glutamate sensitive chloride channels in neurons of invertebrates, leading to paralysis by hyperpolarisation of these cells and blocking signal transfer. Milbemycin A3 Oxime is also an anthelmintic. Formulations containing milbemycin A3 oxime, in combination with milbemycin A4 oxime, have been used in the treatment of parasitic infections in dogs.