Profenamine

Profenamine's anti-Parkinson action can be attributed to its anticholinergic properties. Profenamine partially blocks central (striatal) cholinergic receptors, thereby helping to balance cholinergic and dopaminergic activity in the basal ganglia; salivation may be decreased, and smooth muscle may be relaxed. Drug-induced extrapyramidal symptoms and those due to parkinsonism may be relieved, but tardive dyskinesia is not alleviated and may be aggravated by anticholinergic effects. Profenamine's local anesthetic effect is due to its antagonism of the NMDA glutamate receptor. Glutamate is recognized as an important transmitter in nociceptive pathways, and the N-methyl-D-aspartate (NMDA) subtype of the glutamate receptor, in particular, has been implicated in the mediation of neuropathic pain. Excessive release of glutamate at NMDA receptors on dorsal horn neurons of the spinal cord results in hyperactivation and hypersensitivity of these receptors (perceived as hyperalgesia), thought to be an integral feature of neuropathic pain.