Medical uses

Use in medicine to treat GERD (Gastro esophagel reflux disease), gastric and duodenum ulceration and gastritis.

Use in Helicobacter pylori eradication

Omeprazole is combined with the antibiotics clarithromycin and amoxicillin (or metronidazole in penicillin-hypersensitive patients) in the 7–14 day eradication triple therapy for Helicobacter pylori. Infection by H. pylori is the causative factor in the majority of peptic and duodenal ulcers.^[3]

Mechanism of Action

Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase in the gastric parietal cell. By acting specifically on the proton pump, omeprazole blocks the final step in acid production, thus reducing gastric acidity.^[4]

Adverse effects

Some of the most frequent side effects of omeprazole (experienced by over 1% of those taking the drug) are headache, diarrhea, abdominal pain, nausea, dizziness, trouble awakening and sleep deprivation, although in clinical trials the incidence of these effects with omeprazole was mostly comparable to that found with placebo.^[5] Other side effects may include iron and vitamin B12 deficiency, although there is very little evidence to support this.^[6]

Proton pump inhibitors may be associated with a greater risk of osteoporosis related fractures^[7][8] and Clostridium difficile-associated diarrhea.^[6][9] Patients are frequently administered the drugs in intensive care as a protective measure against ulcers, but this use is also associated with a 30% increase in occurrence of pneumonia.^[6][10] The risk of community-acquired pneumonia may also be higher in people taking PPIs.^[6]

Since their introduction, proton pump inhibitors (especially omeprazole) have been associated with several cases of acute tubulointerstitial nephritis, an inflammation of the kidneys that often occurs as an adverse drug reaction.^[6][11][12]

PPI use has also been associated with fundic gland polyposis.^[13]