dextromethorphan is another ancillary drug some PD patients use.

(was unaware of the following properties of this drug )

Dextromethorphan: d-isomer of the codeine analog of levorphanol; dextromethorphan shows high affinity binding to several regions of the brain, including the medullary cough center; this compound is an NMDA receptor antagonist (n-methyl-d-aspartate receptors) and acts as a noncompetitive channel blocker; it is one of the widely used antitussives, and is also used to study the involvement of glutamate receptors in neurotoxicity.