An anti-diarrhoeal drug is any medication which provides symptomatic relief for diarrhoea.
Morphine is a strong opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as an analgesic. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are available as MS-Contin, Kadian, and other brand names as well as generically.
Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid use disorder. It is used to treat chronic pain, and it is also used to treat addiction to heroin or other opioids. Prescribed for daily use, the medicine relieves cravings and removes withdrawal symptoms. Withdrawal management using methadone can be accomplished in less than a month, or it may be done gradually over a longer period of time, or simply maintained for the rest of the patient's life. While a single dose has a rapid effect, maximum effect can take up to five days of use. After long-term use, in people with normal liver function, effects last 8 to 36 hours. Methadone is usually taken by mouth and rarely by injection into a muscle or vein.
Oxycodone, sold under various brand names such as Roxicodone and OxyContin, is a semi-synthetic opioid used medically for treatment of moderate to severe pain. It is highly addictive and is a commonly abused drug. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.
Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation.
Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work in the brain to produce a variety of effects, including pain relief. As a class of substances, they act on opioid receptors to produce morphine-like effects.
Buprenorphine, sold under the brand name Subutex among others, is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection, as a skin patch (transdermal), or as an implant. For opioid use disorder, it is typically started when withdrawal symptoms have begun and for the first two days of treatment under direct observation of a health-care provider.
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors.
Opioid-induced hyperalgesia (OIH) or opioid-induced abnormal pain sensitivity, also called paradoxical hyperalgesia, is an uncommon condition of generalized pain caused by the long-term use of high dosages of opioids such as morphine, oxycodone, and methadone. OIH is not necessarily confined to the original affected site. This means that if the person was originally taking opioids due to lower back pain, when OIH appears, the person may experience pain in the entire body, instead of just in the lower back. Over time, individuals taking opioids can also develop an increasing sensitivity to noxious stimuli, even evolving a painful response to previously non-noxious stimuli (allodynia). This means that if the person originally felt pain from twisting or from sitting too long, the person might now additionally experience pain from a light touch or from raindrops falling on the skin.
Lubiprostone, sold under the brand name Amitiza among others, 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 μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(mu)-opioid peptide (MOP) receptors. The prototypical μ-opioid receptor agonist is morphine, the primary psychoactive alkaloid in opium and for which the receptor was named, with mu being the first letter of Morpheus, the compound's namesake in the original Greek. It is an inhibitory G-protein coupled receptor that activates the Gi alpha subunit, inhibiting adenylate cyclase activity, lowering cAMP levels.
PEGylation is the process of both covalent and non-covalent attachment or amalgamation of polyethylene glycol polymer chains to molecules and macrostructures, such as a drug, therapeutic protein or vesicle, which is then described as PEGylated. PEGylation affects the resulting derivatives or aggregates interactions, which typically slows down their coalescence and degradation as well as elimination in vivo.
Methylnaltrexone, used in form of methylnaltrexone bromide, is a medication that acts as a peripherally acting μ-opioid receptor antagonist that acts to reverse some of the side effects of opioid drugs such as constipation without significantly affecting pain relief or precipitating withdrawals. Because MNTX is a quaternary ammonium cation, it cannot cross the blood–brain barrier, and so has antagonist effects throughout the body, counteracting effects such as itching and constipation, but without affecting opioid effects in the brain such as pain relief. However, since a significant fraction of opioid analgesia can be mediated by opioid receptors on peripheral sensory neurons, particularly in inflammatory conditions such as arthritis, traumatic or surgical pain, MNTX may increase pain under such circumstances.
Macrogol, also known as polyethylene glycol (PEG), is used as a medication to treat constipation in children and adults. It is also used to empty the bowels before a colonoscopy. It is taken by mouth. Benefits usually occur within three days. Generally it is only recommended for up to two weeks. It is also used as an excipient.
An opiate, is an alkaloid substance derived from opium It has a different meaning from the similar term opioid, used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain. Opiates are alkaloid compounds naturally found in the opium poppy plant Papaver somniferum. The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine. Opiates have long been used for a variety of medical conditions with evidence of opiate trade and use for pain relief as early as the eighth century AD. Most opiates are considered drugs with moderate to high abuse potential and are listed on various "Substance-Control Schedules" under the Uniform Controlled Substances Act of the United States of America.
(+)-Naloxone (dextro-naloxone) is a drug which is the opposite enantiomer of the opioid antagonist drug (−)-naloxone. Unlike (-)-naloxone, (+)-naloxone has no significant affinity for opioid receptors, but instead has been discovered to act as a selective antagonist of Toll-like receptor 4. This receptor is involved in immune system responses, and activation of TLR4 induces glial activation and release of inflammatory mediators such as TNF-α and Interleukin-1.
Naldemedine is a medication that is used for the treatment of opioid-induced constipation in adults with chronic non-cancer pain. It is a peripherally acting μ-opioid receptor antagonist and was developed by Shionogi. Clinical studies have found it to possess statistically significant effectiveness for these indications and to be generally well tolerated, with predominantly mild to moderate gastrointestinal side effects. Effects indicative of central opioid withdrawal or impact on the analgesic or miotic effects of co-administered opioids have only been observed in a small number of patients.
Eluxadoline, sold under the brand names Viberzi and Truberzi, is a medication taken by mouth for the treatment of diarrhea and abdominal pain in individuals with diarrhea-predominant irritable bowel syndrome (IBS-D). It was approved for use in the United States in 2015. The drug originated from Janssen Pharmaceutica and was developed by Actavis.
Bevenopran is a peripherally acting μ-opioid receptor antagonist that also acts on δ-opioid receptors and was under development by Cubist Pharmaceuticals for the treatment of chronic opioid-induced constipation. It reached phase III clinical trials for this indication before being discontinued.
Peripherally acting μ-opioid receptor antagonists (PAMORAs) are a class of chemical compounds that are used to reverse adverse effects caused by opioids interacting with receptors outside the central nervous system (CNS), mainly those located in the gastrointestinal tract. PAMORAs are designed to specifically inhibit certain opioid receptors in the gastrointestinal tract and with limited ability to cross the blood–brain barrier. Therefore, PAMORAs do not affect the analgesic effects of opioids within the central nervous system.
