Fenpiprane

The enteric nervous system (ENS) or intrinsic nervous system is one of the main divisions of the autonomic nervous system (ANS) and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the sympathetic and parasympathetic nervous systems, although it may be influenced by them. The ENS is nicknamed the "second brain". It is derived from neural crest cells.

Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may occur over a long time, sometimes for years. IBS can negatively affect quality of life and may result in missed school or work (absenteeism) or reduced productivity at work (presenteeism). Disorders such as anxiety, major depression, and chronic fatigue syndrome are common among people with IBS.

Fluvoxamine, sold under the brand name Luvox and Faverin among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is primarily used to treat major depressive disorder and obsessive–compulsive disorder (OCD), but is also used to treat anxiety disorders such as panic disorder, social anxiety disorder, and post-traumatic stress disorder.

Aripiprazole, sold under the brand names Abilify and Aristada among others, is an atypical antipsychotic. It is primarily used in the treatment of schizophrenia and bipolar disorder. Other uses include as an add-on treatment in major depressive disorder, tic disorders and irritability associated with autism. It is taken by mouth or injection into a muscle. A Cochrane review found low-quality evidence of effectiveness in treating schizophrenia.

Hydroxyzine, sold under the brand names Atarax, Vistaril and others, is an antihistamine medication. It is used in the treatment of itchiness, insomnia, anxiety, and nausea, including that due to motion sickness. It is used either by mouth or injection into a muscle.

Bethanechol is a parasympathomimetic choline carbamate that selectively stimulates muscarinic receptors without any effect on nicotinic receptors. Unlike acetylcholine, bethanechol is not hydrolyzed by cholinesterase and will therefore have a long duration of action. Bethanechol is sold under the brand names Duvoid (Roberts), Myotonachol (Glenwood), Urecholine and Urocarb (Hamilton). The name bethanechol refers to its structure as the urethane of beta-methylcholine.

Domperidone, sold under the brand name Motilium among others, is a dopamine antagonist medication which is used to treat nausea and vomiting and certain gastrointestinal problems like gastroparesis. It raises the level of prolactin in the human body and is used to induce and promote breast milk production. It may be taken by mouth or rectally.

Simeticone (INN), also known as simethicone (USAN), is an anti-foaming agent used to reduce bloating, discomfort or pain caused by excessive gas.

Alosetron, sold under the brand name Lotronex among others, is a 5-HT₃ antagonist used for the management of severe diarrhea-predominant irritable bowel syndrome (IBS) in females only.

The Bristol stool scale is a diagnostic medical tool designed to classify the form of human faeces into seven categories. It is used in both clinical and experimental fields.

Mosapride is a gastroprokinetic agent that acts as a selective 5HT₄ agonist. The major active metabolite of mosapride, known as M1, additionally acts as a 5HT₃ antagonist, which accelerates gastric emptying throughout the whole of the gastrointestinal tract in humans, and is used for the treatment of gastritis, gastroesophageal reflux disease, functional dyspepsia and irritable bowel syndrome. It is recommended to be taken on an empty stomach (i.e. at least one hour before food or two hours after food).

Acute esophageal necrosis (AEN), black esophagus, or Gurvits syndrome is a rare esophageal disorder. AEN defines itself with dark pigmentation of the esophagus, found during an upper gastrointestinal endoscopy. Pigmentation is usually black friable mucosa. The disorder is extremely rare, as only 89 patients over a span of 40 years have received this diagnosis. Specific study of the disorder's mortality rate is mentioned at 31.8%, but new research suggests mortality rates vary from 30–50%. The exact triggering mechanism for this disorder is still unknown, but is likely multifactorial.

Cinitapride (trade names Cintapro, Pemix) is a gastroprokinetic agent and antiemetic agent of the benzamide class which is marketed in India, Mexico, Pakistan and Spain. It acts as an agonist of the 5-HT₁ and 5-HT₄ receptors and as an antagonist of the 5-HT₂ receptors.

Fedotozine is an opioid drug of the arylacetamide series which acts as a peripherally specific selective κ₁-opioid receptor agonist with preference for the κ_1A subtype. It was under investigation for the treatment of gastrointestinal conditions like irritable bowel syndrome and functional dyspepsia and made it to phase III clinical trials, but ultimately development was discontinued and it was never marketed.

Ulimorelin is a drug with a modified cyclic peptide structure which acts as a selective agonist of the ghrelin/growth hormone secretagogue receptor (GHSR-1a).. Unlike many related drugs, ulimorelin has little or no effect on growth hormone (GH) release in rats. However, like ghrelin and other ghrelin agonists, ulimorelin does stimulate GH release with concomitant increases in insulin-like growth factor 1 (IGF-1) in humans. It has been researched for enhancing gastrointestinal motility, especially in gastroparesis and in aiding recovery of bowel function following gastrointestinal surgery, where opioid analgesic drugs used for post-operative pain relief may worsen existing constipation. While ulimorelin has been shown to increase both upper and lower gastrointestinal motility in rats, and showed promising results initially in humans, it failed in pivotal clinical trials in post operative ileus.