Profenamin

5.2

4.77

166-168

64.5 °C

N - Nervous system

QN - Nervous system

Profenamine, a phenothiazine and antidyskinetic, is used in the treatment of Parkinson's disease. By improving muscle control and reducing stiffness, this drug permits more normal movements of the body as the disease symptoms are reduced. It is also used to control severe reactions to certain medicines such as reserpine, phenothiazines, chlorprothixene, thiothixene, loxapine, and haloperidol. Unlike other NMDA antagonists, profenamine — because of its anticholinergic action — is largely devoid of neurotoxic side effects. Profenamine also has a slight antihistaminic and local anesthetic effect.

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.

Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.