Levomethorphan ( L-stereoisomer of racemethorphan) is an opioid analgesic of the morphinan family that has never been marketed. Levomethorphan is a methylated prodrug of levorphanol, that undergoes hepatic demethylation, converting it to the active form. Levomethorphan (via it’s active form levorphanol)functions as a potent agonist of all three of the opioid receptors, μ, κ (κ1 and κ3 but notably not κ2), and δ, as an NMDA receptor antagonist, and as a serotonin-norepinephrine reuptake inhibitor. Via activation of the KOR, levomethorphan can produce dysphoria and psychotomimetic effects such as dissociation and hallucinations. Levomethorphan is listed under the Single Convention on Narcotic Drugs 1961 and is regulated like morphine in most countries. In the United States it is a Schedule II Narcotic controlled substance.

Dextromethorphan D6 is a weak uncompetitive antagonist of the NMDA receptor. Dextromethorphan is also acts at nicotinic receptors, sigma-1 rcptor and serotonin and norepinephrine transporters. The incorporation of deuterium serves to reduce dextromethorphan first-pass liver metabolism. AVP-786 is an oral formulation of a combination of deuterated (d6)-dextromethorphan and an ultra-low dose of quinidine. Avanir Pharmaceuticals launched a phase III development program of AVP-786 for the treatment of agitation in patients with Alzheimer's disease.

Dextromethorphan D6 is a weak uncompetitive antagonist of the NMDA receptor. Dextromethorphan is also acts at nicotinic receptors, sigma-1 rcptor and serotonin and norepinephrine transporters. The incorporation of deuterium serves to reduce dextromethorphan first-pass liver metabolism. AVP-786 is an oral formulation of a combination of deuterated (d6)-dextromethorphan and an ultra-low dose of quinidine. Avanir Pharmaceuticals launched a phase III development program of AVP-786 for the treatment of agitation in patients with Alzheimer's disease.

Menthol, (+)- is a fragrance ingredient used in decorative cosmetics, fine fragrances, shampoos, toilet soaps and other toiletries as well as in non-cosmetic products such as household cleaners and detergents. Recent investigations have provided evidence for menthol to increase cough thresholds. Racementhol is used as a topical analgesic.