Omeprazole
A proton pump inhibitor for reflux disease, peptic ulcers, H. pylori eradication with antibiotics and Zollinger-Ellison syndrome.
Drug card
- How it works
- Blocking the stomach's proton pump (H+/K+ ATPase) to stop acid secretion
- Used for
- Gastroesophageal reflux disease and erosive esophagitis
- Duodenal and benign gastric ulcers
- H. pylori eradication, with clarithromycin and amoxicillin
- Zollinger-Ellison syndrome
- Known for
- C. difficile diarrhea
- Fractures with long-term use
- Low magnesium with long-term use
- Its name
- -prazole means a proton pump inhibitor
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does omeprazole work?
A substituted benzimidazole prodrug, activated by acid inside parietal cells, that forms a disulfide bond with the H+/K+ ATPase and blocks basal and stimulated acid output for up to about 3 days. It also inhibits CYP2C19, raising levels of drugs such as citalopram and phenytoin and lowering clopidogrel's active metabolite.
Like other proton pump inhibitors: PPIs are prodrugs. They collect in the acidic canaliculi of gastric parietal cells, where acid turns them into an active sulfenamide that binds the H+/K+ ATPase (the proton pump) through covalent disulfide bonds. This shuts off the last step of acid secretion, basal and stimulated alike, and because the bond is irreversible the effect outlasts the drug's short stay in the blood.
Uses
What is omeprazole used for?
- Gastroesophageal reflux disease and erosive esophagitis
- Duodenal and benign gastric ulcers
- H. pylori eradication, with clarithromycin and amoxicillin
- Zollinger-Ellison syndrome
Side effects
Side effects of omeprazole
- C. difficile diarrheaKnown forSerious
- Fractures with long-term useKnown forSerious
- Low magnesium with long-term useKnown forSerious
- Headache
- Abdominal pain
- Nausea and vomiting
- Diarrhea
- Flatulence
- Vitamin B12 deficiency after years of use
- Acute interstitial nephritisSerious
- Severe skin reactions (such as SJS/TEN)Serious
- Allergic reactions, including anaphylaxisSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Avoid with clopidogrel: omeprazole lowers its active metabolite and its antiplatelet effect.
- Contraindicated with rilpivirine; avoid with atazanavir and nelfinavir, whose levels fall.
- Monitor INR with warfarin and levels of tacrolimus and phenytoin; consider pausing it during high-dose methotrexate.
- Symptom relief does not rule out stomach cancer; investigate a poor response.
Remember it
A way to remember it
CLIMB
- C
- C. difficile diarrhea
- L
- Lupus erythematosus, cutaneous or systemic
- I
- Interstitial nephritis
- M
- Magnesium falls (hypomagnesemia)
- B
- B12 deficiency
Five less common but serious PPI risks to remember, alongside fractures with long-term use.
Written for biofideX
Its name
-prazole means proton pump inhibitor
Omeprazole, esomeprazole, lansoprazole and pantoprazole block the H+/K+ ATPase of parietal cells. Aripiprazole, an antipsychotic, ends in -piprazole, which WHO now discourages.
- Every drug name stem
Its class
Proton pump inhibitors
Other proton pump inhibitors with a card:
Easily mixed up with H2 receptor antagonists.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Stomach and gut
Omeprazole is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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