Glutamate antagonists for treatment of neuropathic pain

An altered glutamatergic transmission within the central nervous system is supposed to be involved in the generation and propagation of neuropathic pain. Results from experimental studies with animal models of neuropathic pain demonstrate that glutamate antagonists have a positive effect on various parameters. Clinical studies with the NMDA-receptor antagonists ketamine, amantadine, memantine and dextromethorphan and with the antiepileptics gabapentin and lamotrigine,which reduce presynaptic release of glutamate, have been performed. They have shown that most of these substances can reduce neuropathic pain. Important side effects of the NMDA receptor antagonists are hallucination and agitation, whereas tiredness and dizziness are the ones of the antiepileptics. Till now, glutamate antagonists are not drugs of first choice for the treatment of neuropathic pain. However, they are an effective alternative in case the established drugs are not helpful or are not tolerated well.