Opiren (Lansoprazole)

Lansoprazole, a proton pump inhibitor, is used to treat conditions associated with excess gastric acid secretion.

• Gastro‑oesophageal reflux disease (GERD): alleviates heartburn and esophageal irritation by maintaining higher gastric pH.
• Erosive esophagitis: promotes healing of acid‑induced esophageal lesions.
• Peptic ulcer disease: supports ulcer healing and prevents recurrence by suppressing acid.
• Helicobacter pylori eradication (in combination therapy): enhances the effectiveness of antibiotic regimens by reducing gastric acidity.

• Lansoprazole irreversibly binds to the H+/K+ ATPase enzyme (the gastric proton pump) located on the secretory surface of parietal cells. By blocking this final step of acid production, it markedly reduces both basal and stimulated gastric acid secretion, leading to an increase in gastric pH and providing a prolonged acid‑suppressive effect. The inhibition is sustained for up to 72 hours, allowing once‑daily dosing in most treatment regimens.

Lansoprazole may be associated with a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate intensity.
• Diarrhea: loose stools, usually transient.
• Nausea: occasional feeling of queasiness.
• Abdominal pain: mild discomfort in the stomach area.
• Flatulence: increased intestinal gas.
• Constipation: reduced bowel movements.

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis): rash, swelling, difficulty breathing.
• Clostridioides difficile infection: persistent watery diarrhea, abdominal cramping.
• Low magnesium levels (hypomagnesemia): muscle cramps, irregular heartbeat.
• Bone fractures: increased risk with long‑term use.
• Acute interstitial nephritis: kidney inflammation, reduced urine output.
• Liver enzyme elevation: signs of hepatic injury.

When prescribing Lansoprazole, several safety considerations should be observed.

• Indication assessment: confirm diagnosis of acid‑related disorder before initiating therapy.
• Duration of therapy: limit long‑term use to the shortest period required to achieve clinical goals.
• Monitoring electrolytes: check serum magnesium and potassium during prolonged treatment.
• Concomitant medications: evaluate need for dose adjustment of drugs dependent on gastric pH (e.g., ketoconazole, atazanavir).
• Pregnancy and lactation: use only if potential benefit justifies potential risk; consult healthcare provider.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Lansoprazole can affect the pharmacokinetics of several co‑administered medicines.

Major Interactions (Avoid)

• Antifungal agents (e.g., ketoconazole, itraconazole): reduced absorption due to increased gastric pH.
• HIV protease inhibitors (e.g., atazanavir, nelfinavir): decreased plasma concentrations.
• Clopidogrel: diminished antiplatelet effect.
• Warfarin: potential increase in INR, requiring close monitoring.
• Methotrexate (high dose): enhanced toxicity from reduced renal clearance.

Moderate Interactions (Monitor Closely)

• Digoxin: may increase serum levels.
• Diazepam: increased absorption leading to higher plasma concentrations.
• Iron salts: decreased iron absorption, consider separate dosing.
• Vitamin B12: prolonged use may impair absorption, monitor levels.
• Calcium carbonate: may affect drug dissolution, separate administration recommended.