Omeprazole Arrow Lab (Omeprazole)

Omeprazole acts on the gastric acid secretion pathway and is indicated for several acid‑related disorders.

• Gastro‑oesophageal reflux disease: provides relief of heartburn and promotes healing of erosive esophagitis.
• Peptic ulcer disease: supports ulcer healing and reduces risk of recurrence.
• Zollinger‑Ellison syndrome: controls excessive gastric acid secretion associated with gastrin‑producing tumours.
• NSAID‑induced ulcer prophylaxis: lowers the risk of ulcer formation in patients on long‑term non‑steroidal anti‑inflammatory drugs.

• Omeprazole is a benzimidazole‑derived proton pump inhibitor that irreversibly binds to the H+/K+‑ATPase enzyme located on the secretory surface of gastric parietal cells. By inhibiting this final step of acid production, it markedly reduces both basal and stimulated gastric acidity, allowing mucosal healing and symptom control.

Adverse reactions to omeprazole are generally mild but can vary in frequency.

Common Side Effects

• Headache: mild, transient headache reported in clinical studies.
• Diarrhoea: loose stools occurring during early treatment.
• Nausea: occasional feeling of queasiness.
• Abdominal pain: mild discomfort in the stomach region.
• Flatulence: increased intestinal gas.
• Constipation: reduced bowel movements.

Serious or Rare Side Effects

• Severe allergic reaction: rash, itching, swelling, or difficulty breathing.
• Clostridioides difficile infection: persistent watery diarrhoea.
• Low magnesium levels: muscle cramps, irregular heartbeat, or seizures.
• Bone fractures: increased risk with long‑term use.
• Liver enzyme elevation: abnormal liver function tests.

When using Omeprazole, certain safety considerations should be observed.

• Assess renal function: adjust use in patients with severe kidney impairment.
• Review concomitant medications: potential for altered absorption of drugs requiring acidic pH.
• Monitor long‑term therapy: evaluate need for continued use after 12 months.
• Pregnancy and lactation: use only if clearly needed after risk‑benefit assessment.
• Elderly patients: start with the lowest effective dose and monitor for adverse effects.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Omeprazole may interact with several medicines; awareness of interaction severity guides clinical decisions.

Major Interactions (Avoid)

• Clopidogrel: reduced antiplatelet effect, increasing cardiovascular risk.
• Atazanavir: decreased absorption leading to therapeutic failure.
• Methotrexate (high dose): increased serum levels and toxicity risk.

Moderate Interactions (Monitor Closely)

• Warfarin: potential alteration of INR values.
• Digoxin: possible increase in serum concentration.
• Phenytoin: reduced plasma concentration.
• Diazepam: enhanced sedation effects.