Omeprazole Grindeks (Omeprazole)

Omeprazole is a proton pump inhibitor that decreases gastric acid production in the stomach.

• Gastro‑oesophageal reflux disease (GERD): provides relief of heartburn and promotes healing of erosive esophagitis.
• Peptic ulcer disease (gastric and duodenal ulcers): accelerates ulcer healing and reduces risk of recurrence.
• Zollinger‑Ellison syndrome: controls excessive gastric acid secretion associated with gastrin‑producing tumors.
• NSAID‑induced ulcer prophylaxis: helps prevent ulcer formation in patients receiving long‑term non‑steroidal anti‑inflammatory drugs.

• Omeprazole selectively and irreversibly binds to the H⁺/K⁺‑ATPase enzyme (the gastric proton pump) located on the secretory surface of parietal cells. By inhibiting this final step of acid secretion, it markedly reduces both basal and stimulated gastric acid output, leading to an increased gastric pH and allowing ulcer healing and symptom relief.

Omeprazole may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Headache: mild to moderate intensity.
• Abdominal pain: discomfort or cramping in the stomach area.
• Diarrhoea: loose, watery stools.
• Nausea: feeling of sickness or urge to vomit.
• Flatulence: excess gas in the gastrointestinal tract.
• Constipation: difficulty passing stools.

Serious or Rare Side Effects

• Severe allergic reactions (anaphylaxis, angioedema): swelling, difficulty breathing.
• Clostridioides difficile infection: severe colitis presenting with watery diarrhoea.
• Hypomagnesemia: low magnesium levels causing muscle cramps or arrhythmias.
• Stevens‑Johnson syndrome/toxic epidermal necrolysis: serious skin reactions.
• Hepatic enzyme elevation: increased liver function tests.
• Interstitial nephritis: inflammation of kidney tissue.

Before initiating Omeprazole therapy, certain precautions should be considered to ensure safe use.

• Assess renal function: adjust use in patients with severe kidney impairment.
• Evaluate liver disease: use with caution in moderate to severe hepatic impairment.
• Monitor magnesium levels: especially during prolonged treatment exceeding one year.
• Review concomitant medications: avoid drugs that require gastric acidity for absorption.
• Consider dose adjustment in elderly: start with the lowest effective dose.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Omeprazole can affect the pharmacokinetics of several medicines, leading to clinically relevant interactions.

Major Interactions (Avoid)

• Clopidogrel: reduced conversion to its active metabolite, decreasing antiplatelet effect.
• Atazanavir (and other protease inhibitors): markedly decreased plasma concentrations, risking therapeutic failure.
• Methotrexate: impaired renal clearance, increasing risk of toxicity.

Moderate Interactions (Monitor Closely)

• Digoxin: increased serum concentrations, may require dose adjustment.
• Phenytoin: reduced serum levels, potentially decreasing seizure control.