(-)-Menthol (Levomenthol) is a levo isomer of menthol, an organic compound made synthetically or obtained from peppermint or mint oils with flavoring and local anesthetic properties. When added to pharmaceuticals and foods, menthol functions as a fortifier for peppermint flavors. It also has a counterirritant effect on skin and mucous membranes, thereby producing a local analgesic or anesthetic effect.

Naltrexone hydrochloride (Naltrexone HCl) is a synthetic opioid antagonist used in the prevention of relapse of opiate addiction and alcoholism.

Trimebutine (Mebutin) is a spasmolytic agent that regulates intestinal and colonic motility and relieves abdominal pain with antimuscarinic and weak mu-opioid agonist effects. It is marketed for the treatment of irritable bowel syndrome (IBS) and lower gastrointestinal tract motility disorders, with IBS being one of the most common multifactorial GI disorders. It is used to restore normal bowel function and is commonly present in pharmaceutical mixtures as trimebutine maleate salt form. Trimebutine is not an FDA-Approved/Clinical drug, but it is available in Canada and several other international countries.

Amentoflavone (3',8''-Biapigenin), as a potent inhibitor of CYP3A4 and CYP2C9, can interact with many other medications. CYP3A4 and CYP2C9 are proteins used for drug metabolism in the body. Amentoflavone also is an inhibitor of human cathepsin B. It has antimalarial activity in trials significant affinities towards the Delta-1, kappa opioid receptors (as an antagonist) and binds to benzodiazepine receptors. Amentoflavone may be a potential lead for a new type of anti-inflammatory agents having the dual inhibitory activity of group II phospholipase A2 and cyclooxygenase. Amentoflavone and quercetin differentially exerted suppression of PGE2 biosynthesis via downregulation of COX-2/iNOS expression.

Bevenopran (CB-5945) is a peripheral antagonist of μ-opioid receptor and can be used in studies about the treatment of opioid-induced bowel dysfunction.

Matrine (Vegard), an alkaloid isolated from the Sophora genus, acts as a kappa opioid receptor agonist.

SCH 221510 is an orally available, selective and potent NOP agonist with an EC50 of 12 nM and a Ki of 0.3 nM.SCH 221510 has anxiolytic activity and can be used to study neurological disorders.

Trimebutine maleate (Polibutin) is a weak mu-opioid agonist and has antimuscarinic effects. Trimebutine is an agonist of peripheral mu, delta, and kappa opiate receptors served as a spasmolytic drug for therapy of both chronic and acute abdominal pain.