In June 2010, the first case report appeared of a progressive multifocal leukoencephalopathy being successfully treated with mefloquine. Mefloquine can also act against the JC virus. Administration of mefloquine seemed to eliminate the virus from the patient's body and prevented further neurological deterioration.
Mefloquine alters cholinergic synaptic transmission through both postsynaptic  and presynaptic actions. The postsynaptic action to inhibit acetylcholinesterase changes transmission across synapses in the brain.