Rabeprazole is a second-generation proton pump inhibitor (PPI) that suppresses gastric acid secretion by inhibiting the H+/K+ ATPase enzyme system (proton pump) at the secretory surface of the gastric parietal cell. It is a substituted benzimidazole prodrug that is activated in the acidic environment of the parietal cell canaliculus. It provides rapid, potent, and long-lasting inhibition of gastric acid secretion, making it a cornerstone therapy for acid-related disorders in the Indian population.
Adult: GERD/Erosive Esophagitis: 20mg once daily for 4-8 weeks. Maintenance: 10-20mg once daily. Duodenal/Gastric Ulcer: 20mg once daily for 4-6 weeks. H. pylori Eradication: 20mg twice daily for 7-14 days as part of combination therapy. Hypersecretory Conditions: 60mg once daily, titrated up to 100mg/day or 60mg twice daily.
Note: Swallow the tablet whole with a glass of water; do not crush, split, or chew. Should be taken in the morning, before a meal (preferably breakfast), for optimal acid control. For twice-daily dosing, take before morning and evening meals. Delayed-release tablets are designed to protect the drug from stomach acid.
Rabeprazole is a prodrug. In the highly acidic environment of the parietal cell canaliculus, it is converted to its active sulfenamide form. This active metabolite forms covalent disulfide bonds with cysteine residues (specifically Cys813 and Cys822) on the alpha subunit of the H+/K+ ATPase enzyme (the proton pump), irreversibly inhibiting its function. This prevents the final step of gastric acid secretion, the exchange of intracellular H+ for luminal K+.
Pregnancy: Pregnancy Category B (US FDA). Animal studies have shown no direct fetal harm, but no adequate and well-controlled studies in pregnant women. Use only if clearly needed, at the lowest effective dose for the shortest duration. PPIs are not considered first-line for GERD in pregnancy; antacids/alginates are preferred.
Driving: Rabeprazole is unlikely to impair the ability to drive or use machines. However, dizziness and visual disturbances have been reported rarely; patients experiencing these should avoid such activities.
| Ketoconazole, Itraconazole | Decreased absorption of these azole antifungals due to increased gastric pH. | Major |
| Atazanavir, Rilpivirine | Significantly decreased plasma concentration and loss of efficacy of these HIV protease/NNRTI inhibitors. | Contraindicated/Major |
| Warfarin | Potential increased INR and risk of bleeding due to possible interaction (monitor INR closely). | Moderate |
| Methotrexate | May decrease renal clearance of methotrexate, increasing toxicity risk. | Moderate |
| Digoxin | Increased bioavailability of digoxin due to higher gastric pH. | Moderate |
| Iron Salts (Ferrous sulfate), Dabigatran | Decreased absorption, potentially reducing efficacy. | Moderate |
| Clopidogrel | Theoretical concern due to CYP2C19 inhibition, but Rabeprazole has the weakest interaction among PPIs. Clinical significance is debated. | Minor/Moderate |