Clebopride is a dopamine antagonist drug. It is used to treat functional gastrointestinal disorder such as nausea or vomiting. Unchanged parent drug was the most abundant compound in human urine. Major metabolites included the hydroxylation at benzyl group to yield carbinolamine and its further N-dealkylation product, and the piperidine ring hydroxylation/oxidation metabolite (a lactam).

Bromopride is a dopamine D2 receptor blocker. Bromopride exerts is a gastrointestinal prokinetic exploited clinically for the management of motor disorders of the upper gastrointestinal tract, including functional dyspepsia, gastric stasis of various origins and emesis.

Citiolone (N-acetylhomocysteine thiolactone) is an antioxidant drug used in the treatment of liver diseases.

Spaglumic acid (NAAG) is the β-aspartyl isoform of N-Acetyl-l-aspartylglutamate (isospaglumic Acid is N-(N-Acetyl-l-α-aspartyl)-l-glutamic acid). In eye drops, spaglumic acid is either a magnesium or sodium salt of N-Acetyl-l-aspartylglutamate. Spaglumic acid is a mast cell stabilizer. Thus it is used in allergic conditions such as allergic conjunctivitis. Specifically spaglumic acid is approved in Portugal under the brand name Naabak and in Greece under the brand name Naaxia for use in patients with allergic conjunctivitis. Spaglumic Acid is a peptide neurotransmitter and the third-most-prevalent neurotransmitter in the mammalian nervous system. It is a weak activator of NMDA receptors and a highly selective agonist for mGlu3 receptors. Spaglumic Acid is neuroprotective under non-hydrolysing conditions in vivo.

Rebamipide, an amino acid derivative of 2-(1H)-quinolinone, is used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. It works by enhancing mucosal defense, scavenging free radicals, and temporarily activating genes encoding cyclooxygenase-2. Rebamipide is used in a number of Asian countries including Japan (marketed as Mucosta), South Korea, China, and India (where it is marketed under the trade name Rebagen). It is not approved by the Food and Drug Administration for use in the United States. Studies have shown that rebamipide can fight the damaging effects of NSAIDs on the GIT mucosa.

Ambroxol, a substituted benzylamine, is an active metabolite of bromhexine, which is itself a synthetic derivative of vasicine, the active principle extracted from the plant species Adhatoda vasica. Ambroxol is an expectorant exerting mucokinetic properties, mucociliary activity, stimulation of surfactant production, anti-inflammatory and antioxidative actions and the local anaesthetic effect. Ambroxol was discovered at and has been manufactured by Dr. Karl Thomae GmbH, a division of Boehringer Ingelheim. The ambroxol patent is expired and the drug is available as a generic product from many different companies. Ambroxol was originally developed by Boehringer Ingelheim as a OTC therapy for respiratory disorders related to excessive mucus. Ambroxol's indication is secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport. Boehringer Ingelheim markets the product under various brand names such as Mucosolvan® and Lasolvan®. Ambroxol was identified and found to be a pH-dependent, mixed-type inhibitor of glucocerebrosidase (GCase). Its inhibitory activity was maximal at neutral pH, found in the endoplasmic reticulum, and undetectable at the acidic pH of lysosomes. The pH dependence of Ambroxol to bind and stabilize the enzyme was confirmed. Ambroxol increases both the lysosomal fraction and the enzymatic activity of several mutant GCase variants. This profile of Ambroxol would allow to bind and stabilize GCase in the endoplasmic reticulum (thus preventing its degradation within endoplasmic reticulum), but without affecting GCase in the lysosomes (thus allowing it to degrade glucosylceramide). Indeed, studies showed that Ambroxol treatment significantly increased N370S and F213I mutant GCase activity and protein levels in fibroblasts originally obtained from Gaucher patients. Gaucher's disease is caused by the deficiency of glucocerebrosidase; ambroxol is a chaperone that acts by binding to and stabilising glucocerebrosidase. Zywie (formerly ExSAR Corporation) and Belrose Pharma are developing ambroxol hydrochloride (BEL 0218) for the treatment of type III Gaucher's disease. .

Pempidine is a nicotinic antagonist most commonly used as an experimental tool. It has been used as a ganglionic blocker in the treatment of hypertension but has largely been supplanted for that purpose by more specific drugs. In preclinical models Pempidine blocks the effects of intravenous nicotine and of peripheral vagal stimulation on the blood pressure; it also causes dilatation of the pupil after removal of the sympathetic innervation. On the guinea-pig ileum, the predominant effect of the compound is to inhibit nicotine contractions. Pempidineis well absorbed from the gastrointestinal tract as judged by (a) the low ratio (6.9) of oral to intravenous toxicities, (b) the rapid development of mydriasis in mice after oral administration of small doses, and (c) the rapid onset of hypotension when the compound is injected directly into the duodenum of anaesthetized cats. Other actions include neuromuscular paralysis of curare-like type when large doses of the compound are injected intravenously and central effects such as tremors which occur with near toxic doses. In cats with a low blood pressure, large intravenous doses have a slight pressor action.

Etofylline [7-(2-hydroxyethyl)theophylline] is a N-7-substituted derivative of theophylline, a smooth muscle relaxant. Etofylline is used to relieve bronchoconstriction. It may act as a phosphodiesterase inhibitor and adenosine receptor antagonist.

Acivicin is a modified amino acid and structural analog of glutamine, that irreversibly inhibits glutamine-dependent amidotransferases involved in nucleotide and amino acid biosynthesis. Acivicin is a potent antitumor agent that induces apoptosis in human lymphoblastoid cells. Phase I dose-escalating studies conducted in cancer patients administered acivicin showed reversible, dose-limiting CNS toxicity, characterized by lethargy, confusion and decreased mental status.

Methylthiouracil is an orally active thyroid enzyme activity inhibitor. Methylthiouracil was introduced in the mid-1940s for the treatment of hyperthyroidism. Methylthiouracil is no longer in clinical use in most countries, although it may be used to a limited degree in some eastern European countries. Methylthiouracil possess anti-inflammatory effects in vitro and in vivo and was found effective in a murine model of sepsis.