Mepraz (Omeprazole)

Omeprazole acts on the gastric proton pump to lower acid secretion, making it useful for several acid‑related disorders.

• Gastro‑oesophageal reflux disease (GERD): provides symptomatic relief and promotes healing of esophageal irritation.
• Peptic ulcer disease: supports ulcer healing and reduces recurrence.
• NSAID‑induced ulcer prophylaxis: lowers risk of ulcer formation in patients taking non‑steroidal anti‑inflammatory drugs.
• Zollinger‑Ellison syndrome: controls excessive gastric acid production associated with gastrin‑secreting tumors.

• Omeprazole 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 production, it markedly reduces basal and stimulated gastric acid secretion, leading to an increase in gastric pH.

Omeprazole is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Headache: mild to moderate pain often resolving without treatment.
• Diarrhea: loose stools that may be transient.
• Abdominal pain or discomfort: occasional stomach cramps or bloating.
• Nausea: feeling of sickness, sometimes with vomiting.
• Flatulence: increased gas production.
• Constipation: reduced bowel movements.

Serious or Rare Side Effects

• Clostridioides difficile infection: severe colitis presenting with watery diarrhea.
• Severe allergic reactions: rash, swelling, or anaphylaxis requiring immediate medical attention.
• Low magnesium levels (hypomagnesemia): can cause muscle cramps, irregular heartbeat, or seizures.
• Vitamin B12 deficiency: may develop with long‑term use, leading to anemia.
• Bone fractures: increased risk of hip, wrist, or spine fractures with prolonged therapy.

• Before initiating omeprazole therapy, consider the following precautions to ensure safe use.
• Assess renal and hepatic function: adjust use in patients with severe impairment.
• Monitor long‑term use: evaluate the need for continued therapy to avoid unnecessary exposure.
• Elderly patients: use the lowest effective dose due to higher risk of adverse effects.
• Concurrent use with clopidogrel: consider alternative therapy as omeprazole may reduce antiplatelet effect.
• Pregnancy and breastfeeding: weigh potential benefits against unknown risks; consult a healthcare professional.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Omeprazole can affect the plasma concentrations of several medicines; interactions are classified by their clinical significance.

Major Interactions (Avoid)

• Atazanavir: reduced absorption leading to loss of antiviral efficacy.
• Nelfinavir: decreased plasma levels compromising HIV treatment.
• Rilpivirine: markedly lower exposure, risking treatment failure.
• Clopidogrel: reduced conversion to active metabolite, diminishing antiplatelet activity.

Moderate Interactions (Monitor Closely)

• Warfarin: possible increase in INR, requiring closer coagulation monitoring.
• Digoxin: may raise serum levels, necessitating dosage adjustment.
• Methotrexate: increased toxicity risk, especially at high doses.
• Phenytoin: altered levels, monitor seizure control.
• Ketoconazole: decreased absorption, may need dose modification.