H2 Receptor Antagonists
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H2 Receptor Antagonists
H2 antagonists, sometimes referred to as H2RAs and also called H2 blockers, are a class of pharmaceutical drug, medications that block the action of histamine at the histamine H2 receptor, histamine H2 receptors of the parietal cells in the stomach. This decreases the production of gastric acid, stomach acid. H2 antagonists can be used in the treatment of dyspepsia, peptic ulcers and gastroesophageal reflux disease. They have been surpassed by proton pump inhibitors (PPIs). The PPI omeprazole was found to be more effective at both healing and alleviating symptoms of ulcers and reflux oesophagitis than the H2 blockers ranitidine and cimetidine. H2 antagonists, which all end in "-tidine", are a type of antihistamine. In general usage, however, the term "antihistamine" typically refers to H1 antagonist, H1 antagonists, which relieve Allergy, allergic reactions. Like the H1 antagonists, some H2 antagonists function as inverse agonists rather than receptor antagonists, due to the con ...
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Allergy
Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include allergic conjunctivitis, red eyes, an itchy rash, sneeze, sneezing, coughing, a rhinorrhea, runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions. Common allergens include pollen and certain foods. Metals and other substances may also cause such problems. Food, insect stings, and medications are common causes of severe reactions. Their development is due to both genetic and environmental factors. The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to FcεRI, a receptor on mast cells or basophils where it triggers ...
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Roxatidine
Roxatidine acetate is a specific and competitive histamine H2 receptor antagonist drug that is used to treat gastric ulcers, Zollinger–Ellison syndrome, erosive esophagitis, gastro-oesophageal reflux disease, and gastritis.BioSpectrum Bureau 1 November 2012Sinhuan's generic heart drug gets production approval/ref> Pharmacodynamic studies showed that 150 mg of roxatidine acetate were optimal in suppressing gastric acid secretion, and that a single bedtime dose of 150 mg was more effective than a dose of 75 mg twice daily in terms of inhibiting nocturnal acid secretion. It was patented in 1979 and approved for medical use in 1986. It is available in countries including China, Japan, Korea, Germany, Italy, the Netherlands, Greece, and South Africa. Synthesis The reductive amination between piperidine (1) and 3-hydroxybenzaldehyde (2) gives 3-(1-piperidinylmethyl)phenol (3). Williamson ether synthesis with ''N''-(3-bromopropyl)phthalimide (4) gives the in ...
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Nizatidine
Nizatidine is a histamine H2 receptor antagonist that inhibits stomach acid production, and is commonly used in the treatment of peptic ulcer disease and gastroesophageal reflux disease. It was patented in 1980 and approved for medical use in 1988. It was developed by Eli Lilly. Medical use Nizatidine is used to treat duodenal ulcers, gastric ulcers, and gastroesophageal reflux disease (GERD/GORD), and to prevent stress ulcers. Adverse effects Side effects are uncommon, usually minor, and include diarrhea, constipation, fatigue, drowsiness, headache, and muscle aches. History and development Nizatidine was developed by Eli Lilly, and was first marketed in 1988. It is considered to be equipotent with ranitidine Ranitidine, previously sold under the brand name Zantac among others, is a medication used to decrease stomach acid production. It was commonly used in treatment of peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellis ... and differs ...
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Famotidine
Famotidine, sold under the brand name Pepcid among others, is a histamine H2 receptor antagonist medication that decreases stomach acid production. It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. It is taken by mouth or by injection into a vein. It begins working within an hour. Common side effects include headache, abdominal pain, diarrhea or constipation, and dizziness. Serious side effects may include pneumonia and seizures. Use in pregnancy appears safe but has not been well studied, while use during breastfeeding is not recommended. Famotidine was patented in 1979 and came into medical use in 1985. It is available as a generic medication. In 2022, it was the 49th most commonly prescribed medication in the United States, with more than 13million prescriptions. Medical uses *Heartburn, acid indigestion, and sour stomach * Treatment for gastric and duodenal ulcers * Treatment for pathologic gastrointesti ...
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Drug Interaction
In pharmaceutical sciences, drug interactions occur when a drug's mechanism of action is affected by the concomitant administration of substances such as foods, beverages, or other drugs. A popular example of drug–food interaction is the effect of grapefruit on the metabolism of drugs. Interactions may occur by simultaneous targeting of receptors, directly or indirectly. For example, both Zolpidem and alcohol affect GABAA receptors, and their simultaneous consumption results in the overstimulation of the receptor, which can lead to loss of consciousness. When two drugs affect each other, it is a drug–drug interaction (DDI). The risk of a DDI increases with the number of drugs used. A large share of elderly people regularly use five or more medications or supplements, with a significant risk of side-effects from drug–drug interactions. Drug interactions can be of three kinds: * additive (the result is what you expect when you add together the effect of each drug take ...
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Ranitidine
Ranitidine, previously sold under the brand name Zantac among others, is a medication used to decrease stomach acid production. It was commonly used in treatment of peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. It can be given by mouth, injection into a muscle, or injection into a vein. In September 2019, the probable carcinogen ''N''-nitrosodimethylamine (NDMA) was discovered in ranitidine products from a number of manufacturers, resulting in recalls. In April 2020, ranitidine was withdrawn from the United States market and suspended in the European Union and Australia due to these concerns. In 2022, these concerns were confirmed in a Taiwanese nationwide population study finding "significant trends of increased liver cancer risk with an increasing dose of ranitidine" (up to 22% higher than control) and increased gastric, pancreatic, lung and overall cancer risk. Common side effects include headaches, and pain or burning s ...
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Quantitative Structure-activity Relationship
Quantitative may refer to: * Quantitative research, scientific investigation of quantitative properties * Quantitative analysis (other) * Quantitative verse, a metrical system in poetry * Statistics, also known as quantitative analysis * Numerical data, also known as quantitative data * Quantification (science) In mathematics and empirical science, quantification (or quantitation) is the act of counting and measuring that maps human sense observations and experiences into quantity, quantities. Quantification in this sense is fundamental to the scientific ... See also * Qualitative {{disambig ...
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Blockbuster Drug
Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management. Drugs are classified in many ways. One of the key divisions is by level of control, which distinguishes prescription drugs (those that a pharmacist dispenses only on the medical prescription) from over-the-counter drugs (those that consumers can order for themselves). Medicines may be classified by mode of action, route of administration, biological system affected, or therapeutic effects. The World Health Organization keeps a list of essential medicines. Drug discovery and drug development are complex and expensive endeavors undertaken by pharmaceutical companies, academic scientists, and governments. As a resu ...
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Tagamet
Cimetidine, sold under the brand name Tagamet among others, is a histamine H2 receptor antagonist that inhibits stomach acid production. It is mainly used in the treatment of heartburn and peptic ulcers. With the development of proton pump inhibitors, such as omeprazole, approved for the same indications, cimetidine is available as an over-the-counter formulation to prevent heartburn or acid indigestion, along with the other H2-receptor antagonists. Cimetidine was developed in 1971 and came into commercial use in 1977. Cimetidine was approved in the United Kingdom in 1976, and was approved in the United States by the Food and Drug Administration in 1979. Medical uses Cimetidine is indicated for the treatment of duodenal ulcers, gastric ulcers, gastroesophageal reflux disease, and pathological hypersecretory conditions. Cimetidine is also used to relieve or prevent heartburn. Side effects Reported side effects of cimetidine include diarrhea, rashes, dizziness, fatigue, ...
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GlaxoSmithKline
GSK plc (an acronym from its former name GlaxoSmithKline plc) is a British Multinational corporation, multinational Pharmaceutics, pharmaceutical and biotechnology company with headquarters in London. It was established in 2000 by a Mergers and acquisitions, merger of Glaxo Wellcome and SmithKline Beecham, which was itself a merger of a number of pharmaceutical companies around the Smith, Kline & French firm. GSK is the tenth largest pharmaceutical company and No. 294 on the 2022 Fortune Global 500, ''Fortune'' Global 500, ranked behind other pharmaceutical companies China Resources, Sinopharm (company), Sinopharm, Johnson & Johnson, Pfizer, Roche, AbbVie, Novartis, Bayer, and Merck & Co., Merck Sharp & Dohme. The company has a primary listing on the London Stock Exchange and is a constituent of the FTSE 100 Index. As of February 2024, it had a Market capitalization, market capitalisation of £69 billion, the eighth largest on the London Stock Exchange. The company developed ...
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Sir James Black
Sir James Whyte Black (14 June 1924 – 22 March 2010) was a Scottish physician and pharmacologist. Together with Gertrude B. Elion and George H. Hitchings, he shared the Nobel Prize for Medicine in 1988 for pioneering strategies for rational drug-design, which, in his case, led to the development of propranolol and cimetidine. Black established a Veterinary Physiology department at the University of Glasgow, where he became interested in the effects of adrenaline on the human heart. He went to work for ICI Pharmaceuticals in 1958 and, while there, developed propranolol, a beta blocker used for the treatment of heart disease. Black was also responsible for the development of cimetidine, an H2 receptor antagonist, a drug used to treat stomach ulcers. Early life and education Black was born on 14 June 1924 in Uddingston, Lanarkshire, the fourth of five sons of a Baptist family which traced its origins to Balquhidder, Perthshire. His father was a mining engineer. He was broug ...
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