Irritable bowel syndrome (IBS), referred to previously as spastic or nervous colon, and spastic bowel, is a functional gastrointestinal disorder characterized by a group of symptoms accompanied together that include abdominal pain and changes in the consistency of bowel movements. These symptoms occur over a long time, often years. It has been classified into four main types depending on whether diarrhea is common, constipation is common, both are common (mixed/alternating), or neither occurs very often. IBS negatively affects quality of life and may result in missed school or work. Disorders such as anxiety, major depression, and chronic fatigue syndrome are common among people with IBS. IBS does not lead to malabsorption.
Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, Crohn's disease and ulcerative colitis being the principal types. Crohn's disease affects the small intestine and large intestine, as well as the mouth, esophagus, stomach and the anus, whereas ulcerative colitis primarily affects the colon and the rectum.
Functional gastrointestinal disorders (FGID), also known as disorders of gut–brain interaction, include a number of separate idiopathic disorders which affect different parts of the gastrointestinal tract and involve visceral hypersensitivity and motility disturbances.
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 women only.
Tegaserod is a 5-HT4 agonist manufactured by Novartis and sold under the names Zelnorm and Zelmac for the management of irritable bowel syndrome and constipation. Approved by the FDA in 2002, it was subsequently removed from the market in 2007 due to FDA concerns about possible adverse cardiovascular effects. Before then, it was the only drug approved by the United States Food and Drug Administration to help relieve the abdominal discomfort, bloating, and constipation associated with irritable bowel syndrome. Its use was also approved to treat chronic idiopathic constipation.
Renzapride is a prokinetic agent and antiemetic which acts as a full 5-HT4 agonist and partial 5-HT3 antagonist. It also functions as a 5-HT2B antagonist and has some affinity for the 5-HT2A and 5-HT2C receptors.
The Rome process and Rome criteria are an international effort to create scientific data to help in the diagnosis and treatment of functional gastrointestinal disorders, such as irritable bowel syndrome, functional dyspepsia and rumination syndrome. The Rome diagnostic criteria are set forth by Rome Foundation, a not for profit 501(c)(3) organization based in Raleigh, North Carolina, United States.
Lubiprostone is a medication used in the management of chronic idiopathic constipation, predominantly irritable bowel syndrome-associated constipation in women and opioid-induced constipation. The drug is owned by Mallinckrodt and is marketed by Takeda Pharmaceutical Company.
The cannabinoid receptor type 2, abbreviated as CB2, is a G protein-coupled receptor from the cannabinoid receptor family that in humans is encoded by the CNR2 gene. It is closely related to the cannabinoid receptor type 1 (CB1), which is largely responsible for the efficacy of endocannabinoid-mediated presynaptic-inhibition, the psychoactive properties of tetrahydrocannabinol (THC), the active agent in cannabis, and other phytocannabinoids (plant cannabinoids). The principal endogenous ligand for the CB2 receptor is 2-Arachidonoylglycerol (2-AG).
Originally synthesized by chemist Wayne E. Kenney, BAY 38-7271 (KN 38-7271) is a drug which is a cannabinoid receptor agonist developed by Bayer AG. It has analgesic and neuroprotective effects and is used in scientific research, with proposed uses in the treatment of traumatic brain injury. It is a full agonist with around the same potency as CP 55,940 in animal studies, and has fairly high affinity for both CB1 and CB2 receptors, with Ki values of 2.91nM at CB1 and 4.24nM at CB2. It has been licensed to KeyNeurotek Pharmaceuticals for clinical development, and was in Phase II trials in 2008 but its development appears to have stopped.
Solabegron is a drug which acts as a selective agonist for the β3 adrenergic receptor. It is being developed for the treatment of overactive bladder and irritable bowel syndrome. It has been shown to produce visceral analgesia by releasing somatostatin from adipocytes.
Prucalopride, brand names Resolor and Motegrity among others, is a drug acting as a selective, high affinity 5-HT4 receptor agonist which targets the impaired motility associated with chronic constipation, thus normalizing bowel movements. Prucalopride was approved for medical use in the European Union in 2009, in Canada in 2011, in Israel in 2014, and in the United States in December 2018. The drug has also been tested for the treatment of chronic intestinal pseudo-obstruction.
Arena Pharmaceuticals, Inc. is an American biopharmaceutical company founded in 1997 and headquartered in San Diego, California. The company has small molecule drugs in development for possible clinical utility in multiple therapeutic areas. The company's most advanced investigational clinical programs are ralinepag in testing for pulmonary arterial hypertension (PAH), etrasimod in evaluation for inflammatory indications and APD371 for the treatment of pain associated with Crohn’s disease. In 2016, the company downsized and shifted its focus to developing new drugs currently being tested in clinical trials. In December 2021, Pfizer announced that it had agreed to acquire Arena for $6.7 billion in cash. In March 2022, it was announced the acquisition by Pfizer had been concluded.
GW-405,833 (L-768,242) is a drug that acts as a potent and selective partial agonist for the cannabinoid receptor subtype CB2, with an EC50 of 0.65 nM and selectivity of around 1200x for CB2 over CB1 receptors. Animal studies have shown it to possess antiinflammatory and anti-hyperalgesic effects at low doses, followed by ataxia and analgesic effects when the dose is increased. Selective CB2 agonist drugs such as GW-405,833 are hoped to be particularly useful in the treatment of allodynia and neuropathic pain for which current treatment options are often inadequate.
Asimadoline (EMD-61753) is an experimental drug which acts as a peripherally selective κ-opioid receptor (KOR) agonist. Because of its low penetration across the blood–brain barrier, asimadoline lacks the psychotomimetic effects of centrally acting KOR agonists, and consequently was thought to have potential for medical use. It has been studied as a possible treatment for irritable bowel syndrome, with reasonable efficacy seen in clinical trials, but it has never been approved or marketed.
Tedalinab (GRC-10693) is a drug developed by Glenmark Pharmaceuticals for the treatment of osteoarthritis and neuropathic pain, which acts as a potent and selective cannabinoid CB2 receptor agonist. It has a very high selectivity of 4700x for CB2 over the related CB1 receptor, has good oral bioavailability and has shown promising safety results and effective analgesic and antiinflammatory actions in early clinical trials. Many related compounds are known, most of which also show high CB2 selectivity.
PF-03550096 is a drug that acts as a potent agonist for the CB2 cannabinoid receptor, with good selectivity over CB1 having Ki values of 7nM at CB2 and 1500nM at CB1. It was originally developed by Pfizer in 2008 as a medication for irritable bowel syndrome, but has only progressed to animal studies.
Cannabinor (PRS-211,375) is a drug which acts as a potent and selective cannabinoid CB2 receptor agonist. It is classed as a "nonclassical" cannabinoid with a chemical structure similar to that of cannabidiol. It has a CB2 affinity of 17.4nM vs 5585nM at CB1, giving it over 300x selectivity for CB2. It showed analgesic effects in animal studies especially in models of neuropathic pain, but failed in Phase IIb human clinical trials due to lack of efficacy.
RQ-00202730 is a benzimidazole derived drug that acts as a potent and highly selective agonist for the CB2 cannabinoid receptor, with a Ki value of 19nM at CB2 and more than 4000x selectivity over CB1, though it also shows some activity as an antagonist of the unrelated 5-HT2B serotonin receptor. It has analgesic and antiinflammatory effects in animal studies, and was developed for the treatment of irritable bowel syndrome, but was ultimately discontinued from development following disappointing results in Phase II clinical trials.
