|( S ) shape (top) and ( R ) shape (bottom)|
|Molecular formula||C 17 H 19 N 3 O 3 S|
|External identifiers / databases|
|Mechanism of action|
|Molar mass||345.42 g · mol -1|
156 ° C
|As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .|
- Treatment of duodenal ulcer ( duodenal ulcer )
- Treatment of gastric ulcer (gastric ulcer )
- Treatment of inflammation of the esophagus caused by reflux of gastric juice ( reflux esophagitis )
- Treatment of symptoms caused by stomach acid flowing back into the esophagus (reflux disease, heartburn)
- Treatment of Zollinger-Ellison Syndrome
- Prevents esophagitis from recurring or ulcers in the stomach and duodenum caused by the use of certain painkillers or anti-rheumatics (so-called non-steroidal anti-inflammatory drugs)
- Combination therapy for Helicobacter pylori infections
type of application
The treatment of acute forms of the diseases mentioned in the Indications section (duodenal ulcer, gastric ulcer, reflux disease and the esophagitis caused by it) is carried out with gastrointestinal omeprazole tablets or capsules; infusion is also possible if necessary .
Hypersensitivity to active ingredient or excipient. Combination with atazanavir . Combination with clarithromycin and simultaneous use of terfenadine , astemizole , cisapride or carbamazepine . According to current recommendations, if possible no administration should take place in combination with clopidogrel (switch to H2-receptor antagonist).
Omeprazole is metabolized in the liver via cytochrome P450 , mainly via the variant CYP2C19 (also cytochrome P450 1A2 ). The cytochrome CYP2C19 is inhibited by omeprazole. However, clinically relevant drug interactions are very rare. The activity of the enzyme CYP2C19 with the breakdown of omeprazole can lead to the temporary accumulation of another active substance or its precursor in the same breakdown pathway. This accumulation can increase the effectiveness of an active ingredient and decrease the effectiveness of a precursor (since one precursor is less converted to the active form). The most common interaction is with vitamin K antagonists. According to data from the Food and Drug Administration, the risk of such an interaction is 0.09 per million prescribed packs of the drug. Interactions with phenytoin or benzodiazepines were even rarer . A mutation of CYP2C19 is also known, which leads to a slower breakdown of all proton pump inhibitors. The mutation occurs in Asia with a frequency of around 20%. There is an interaction with the anticoagulant clopidogrel , which is metabolized by the same enzyme. Since CYP2C19 is inhibited by omeprazole, the conversion of clopidogrel to the active metabolite decreases. This interaction is less common with pantoprazole . The European Medicines Agency advises against simultaneous use .
Use during pregnancy and breastfeeding
Omeprazole is the drug of second choice during pregnancy when antacids or ranitidine or cimetidine are no longer sufficient. If possible, the drug should not be used during pregnancy and breastfeeding unless the doctor deems it absolutely necessary.
Gastrointestinal disorders, increased liver values , skin reactions, fatigue, sleep disorders, dizziness , joint problems, headaches, hair loss, visual, hearing and taste disorders and polyneuropathy were observed as side effects . In addition, therapy with omeprazole leads to a reduced availability of the intrinsic factor , which in turn leads to an insufficient absorption of vitamin B12 . Very rare but dangerous are pancreatitis , hepatitis , changes in the blood count , Stevens-Johnson syndrome , and visual disturbances . According to a 2009 study, the use of proton pump inhibitors could potentially lead to dependence. According to a 2016 study in Bonn, older people who took pantoprazole or omeprazole for a long time had an increased risk of dementia. An investigation of suspected cases to the FDA found a massive increase in the risk of severe kidney disease for proton pump blockers compared to H 2 acid blockers . In 1992, cases of impotence and gynecomastia (breast enlargement) were reported as undesirable side effects of omeprazole.
Use in animals
In cats, omeprazole must be administered twice daily to achieve a significant increase in gastric pH.
In horses, omeprazole must be administered once daily at a dose of 4 mg / kg body weight for the treatment of gastric ulcers ( equine gastric ulcer syndrome ).
Mechanism of action
Omeprazole is a prodrug and is converted at its site of action, the acid-producing parietal cells of the stomach , into the actually active metabolite (a sulfenamide), which irreversibly inhibits the proton potassium ATPase (the “proton pump”) in these cells . This inhibition is triggered by the formation of adducts, since the metabolite adds to the protein with the formation of a disulfide bridge. This leads to a decrease in acid production in the stomach and the pH of the gastric juice increases.
Absorption and distribution in the body
Omeprazole is acid-sensitive and is therefore administered in an enteric dosage form. The maximum plasma concentration is reached after 1–3 hours. The plasma half-life is 40 minutes. 80% of it is excreted in the urine after metabolism in the liver.
The bioavailability is 35% and increases to 60% with repeated administration.
Omeprazole has a stereocenter on the sulfur atom and is used in the form of its magnesium salt both as a racemate [1: 1 mixture of the ( S ) enantiomer and the ( R ) enantiomer] and as a pure ( S ) enantiomer ( esomeprazole ) as Drug.
Omeprazole was the first proton pump inhibitor to be introduced into therapy and, as a well-tolerated gastric drug, became a blockbuster for the British-Swedish pharmaceutical company AstraZeneca in the 1990s . Its omeprazole preparations Antra and Prilosec had annual sales of more than 5 billion euros. Shortly before the patent expiry of omeprazole, AstraZeneca launched a new dosage form in 1998 (it is believed to strengthen its own market position with regard to the expected competition with generic market launches) : the Multiple Unit Pellet System (MUPS). Antra MUPS tablets are compressed from small, enteric coated pellets , which disintegrate rapidly on contact with liquid. This should enable particularly good bioavailability . A therapeutic superiority of the MUPS compared to conventional omeprazole film-coated tablets or capsules has not been proven, but the pellets are easy to use in patients who are fed by tube or who are otherwise unable to swallow tablets. After the patent expiry of omeprazole in 1999, AstraZeneca came onto the market in 2000 with its ( S ) enantiomer ( esomeprazole , Nexium ). Since esomeprazole is metabolized more via CYP2A19 and thus more slowly than racemic omeprazole, the result is a slower lowering of the plasma level and thus better bioavailability compared to the racemate . Due to the mechanism of action of the proton pump inhibitors, the therapeutic relevance is questionable.
One innovation was omeprazole sodium hydrogen carbonate formulations ( Zegerid ) from the US company Santarus in 2004, which do not require an enteric coating and allow additional dosage forms and should release the active ingredient particularly quickly. The combination is available as an oral suspension and as capsules.
Antra MUPS (D), Ecomep (CH), Gastracid (D), Gastrobene (A), Gastroplex (A), Losec (A), Medoprazol (A), Novec (A), Omec (A), Omep (D ), Omeprax (CH), Omezol (CH), Oprazol (CH), Ulcozol (D), Ulnor (D), Progastim (PL), and other generics.
GastroGard (D, A), Pepticure (D), Peptizole (A), Ulcergold (NL)
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