GASTRIC SECRETION INHIBITORS

GASTRIC SECRETION INHIBITORS act at some stage in the control process to inhibit the enzymic or gastric acid secretions of the stomach, with the latter being a major therapeutic target. The neuronal, hormonal and paracrine control of gastric acid secretion from the parietal cells of the gastric mucosa is complex. The pathways involved include acetylcholine via the parasympathetic innervation of the stomach, the hormone gastrin. the paracrine agent histamine and possibly the paracrine hormone gastrin-releasing peptide. Anticholinergic agents have not proved very valuable in the long-run, having a limited ability to reduce acid secretion at doses that can be tolerated in view of widespread side-effects. Some more recently developed agents show gastric-selectivity (they are Mrcholinoceptor-preferring ligands, which may be the reason for their selectivity), e.g. pirenzepine and telenzepine: see muscarinic cholinoceptor antagonists. Gastrin receptor antagonists and gastrin-releasing peptide antagonists have now been developed for experimental use, but it is not yet clear if either will be useful clinically. See BOMBESIN RECEPTOR ANTAGONISTS; CHOLECYSTOKININ RECEPTOR ANTAGONISTS. Histamine H2-receptor antagonists Read more […]

Herb-Drug Interactions: Cocoa

Theobroma cacao L. (Sterculiaceae) Synonym(s) and related species Cacao, Chocolate, Chocolate tree, Theobroma. Pharmacopoeias Chocolate (US Ph 32); Cocoa Butter (US Ph 32); Theobroma Oil (British Pharmacopoeia 2009). Constituents Cocoa seeds contain xanthine derivatives, principally theobromine (1% to 4%), with small amounts of caffeine (up to about 0.4%) and other alkaloids. They are also rich in flavonoids from the flavanol and procyanidin groups, mainly catechin and epicatechin and their polymers. The nibs (cotyledons) are a rich source of cocoa butter (theobroma oil), which contains oleic, stearic, palmitic and linoleic acids. Use and indications The seeds roasted and powdered are the source of cocoa, which is mainly used as a food (in chocolate). Medicinal uses include as a stimulant and as a diuretic; effects that can be attributed to the xanthine content. However, note that theobromine is a much weaker xanthine than caffeine. Cocoa butter is used as an emollient and pharmaceutical excipient. More recently, there has been interest in the possible beneficial effects of cocoa consumption on cardiovascular health, because of its high content of flavonoids. Pharmacokinetics The pharmacokinetics of caffeine Read more […]

ANTIULCEROGENIC AGENTS

ANTIULCEROGENIC AGENTS (or ulcer-healing drugs) are used to promote healing of ulceration of gastric and duodenal peptic ulcers. A number of classes of drugs may be used. See also gastric secretion inhibitors. First, the HISTAMINE H2-ANTAGONISTS are very effective and have considerable usage, e.g. cimetidine. famotidine, nizatidine and ranitidine. These agents decrease gastric acid secretion and promote healing and may be used to treat dyspepsia and oesophagitis of a number of etiologies. Acid production is also very effectively reduced by the newer agents, the proton pump inhibitors, e.g. omeprazole (see GASTRIC PROTON PUMP INHIBITORS). Anticholinergic drugs are only really suitable in the case of agents that show some gastric-selectivity, e.g. pirenzepine and telenzepine (see muscarinic cholinoceptor ANTAGONISTS). They work by reducing the secretion of peptic acid by the stomach mucosa. Some prostaglandin analogues are effective in protecting the mucosa, and are incorporated into some preparations of NSAIDs to offer concurrent protection (though they may cause unacceptable stimulation of the ileum), e.g. misoprostol. (see prostanoid receptor agonists) . Bismuth-containing antacid preparations have been Read more […]