Usage
Rabeprazole is prescribed for the treatment of conditions caused by excessive stomach acid production. These include:
- Gastroesophageal Reflux Disease (GERD): A chronic digestive disease where stomach acid flows back into the esophagus, causing heartburn and other symptoms.
- Duodenal Ulcers: Sores that develop in the lining of the upper part of the small intestine (duodenum).
- Helicobacter pylori (H. pylori) Infection: A bacterial infection that can cause stomach and duodenal ulcers. Rabeprazole is used in combination with antibiotics to eradicate H. pylori.
- Zollinger-Ellison Syndrome: A rare condition characterized by tumors in the pancreas or duodenum that produce excessive amounts of gastrin, a hormone that stimulates acid production.
- Pathological Hypersecretory Conditions: Other conditions where the stomach produces too much acid.
Pharmacological Classification: Rabeprazole is a Proton Pump Inhibitor (PPI).
Mechanism of Action: Rabeprazole works by irreversibly blocking the H+/K+ ATPase enzyme system (proton pump) in the parietal cells of the stomach. This enzyme is crucial for the final step of acid production. By inhibiting this enzyme, Rabeprazole effectively reduces the amount of acid secreted into the stomach.
Alternate Names
- International Nonproprietary Name (INN): Rabeprazole.
- Other names: Rabeprazole sodium.
Brand Names: AcipHex, Pariet, Rabecure, Rabeloc, and others.
How It Works
Pharmacodynamics: Rabeprazole, like other PPIs, exerts its therapeutic effect by suppressing gastric acid secretion. This action creates a less acidic environment in the stomach and duodenum, promoting ulcer healing and relieving GERD symptoms. Rabeprazole has a high bioavailability and a relatively long duration of action.
Pharmacokinetics:
- Absorption: Rabeprazole is administered orally as delayed-release tablets or capsules. The enteric coating protects the drug from degradation in the acidic environment of the stomach, allowing for absorption in the small intestine.
- Metabolism: Primarily metabolized in the liver via the cytochrome P450 (CYP450) enzyme system, specifically CYP2C19 and CYP3A4.
- Elimination: Excreted primarily through the kidneys as metabolites and a small portion via bile in the feces.
Mode of Action: Rabeprazole binds to the H+/K+ ATPase, the proton pump responsible for secreting hydrogen ions (H+) into the stomach lumen. This binding is irreversible, and the pump remains inactive until new pumps are synthesized.
Receptor Binding/Enzyme Inhibition: Rabeprazole specifically inhibits the H+/K+ ATPase enzyme.
Elimination Pathways: Renal excretion (primarily) and hepatic excretion (minor). CYP2C19 and CYP3A4 enzymes are involved in its metabolism.
Dosage
Standard Dosage
Adults:
- GERD: 20 mg orally once daily for 4-8 weeks. Maintenance therapy may be necessary.
- Duodenal Ulcers: 20 mg orally once daily after the morning meal for up to 4 weeks.
- H. pylori Eradication: 20 mg twice daily (with meals) for 7 days in combination with antibiotics like amoxicillin and clarithromycin.
- Zollinger-Ellison Syndrome: Starting dose of 60 mg once daily, adjusted according to individual needs. Doses up to 100 mg once daily or 60 mg twice daily have been used. Treatment continues as long as clinically indicated.
Children:
- GERD (12 years and older): 20 mg orally once daily for up to 8 weeks.
- GERD (1-11 years, 15 kg or more): 10 mg orally once daily.
- GERD (1-11 years, less than 15 kg): 5 mg orally once daily.
- Use is not recommended for children younger than 1 year for GERD and younger than 12 for other indications. Dosing in children for other conditions must be determined by a physician.
Special Cases:
- Elderly Patients: Generally, no dosage adjustment is necessary, but close monitoring is advisable.
- Patients with Renal Impairment: No dosage adjustment is usually needed.
- Patients with Hepatic Dysfunction: Mild to moderate dysfunction – no dosage adjustment needed. Severe dysfunction – dosage adjustment may be required.
- Patients with Comorbid Conditions: Individualized dosage adjustments may be required.
Clinical Use Cases
The listed clinical cases (Intubation, Surgical Procedures, Mechanical Ventilation, ICU use, and Emergency Situations) are not standard indications for Rabeprazole. Its primary use is in managing acid-related disorders, as outlined above. It may be used perioperatively to reduce the risk of aspiration pneumonitis.
Dosage Adjustments
Dosage adjustments are based on individual patient response, renal and hepatic function, and concomitant medications. Therapeutic drug monitoring may be useful in some cases.
Side Effects
Common Side Effects:
Headache, diarrhea, abdominal pain, nausea, vomiting, constipation, flatulence, infection, sore throat, dizziness, asthenia (weakness).
Rare but Serious Side Effects:
Severe allergic reactions (anaphylaxis, angioedema), Clostridium difficile-associated diarrhea, hypomagnesemia, bone fractures (with long-term use), cutaneous and systemic lupus erythematosus, fundic gland polyps.
Long-Term Effects:
Long-term use of rabeprazole can lead to hypomagnesemia, increased risk of fractures, and the development of fundic gland polyps. Regular monitoring of magnesium levels and bone density is recommended with prolonged use.
Adverse Drug Reactions (ADR)
Any of the rare but serious side effects mentioned above should be considered ADRs requiring immediate intervention.
Contraindications
- Hypersensitivity to rabeprazole, substituted benzimidazoles, or any component of the formulation.
- Concomitant use of rilpivirine.
Drug Interactions
Rabeprazole can interact with several drugs, including:
- Methotrexate: Increased methotrexate levels.
- Digoxin: Increased digoxin levels.
- Warfarin and other anticoagulants: Increased risk of bleeding.
- Clopidogrel: Reduced antiplatelet effect.
- Ketoconazole and other azole antifungals: Increased rabeprazole levels.
- Atazanavir and other antiretrovirals: Reduced antiretroviral efficacy.
CYP450 interactions are possible, especially with CYP2C19 and CYP3A4 substrates, inhibitors, or inducers. It’s important to review a comprehensive drug interaction list before prescribing Rabeprazole.
Pregnancy and Breastfeeding
- Pregnancy: Rabeprazole should be used during pregnancy only if the potential benefit outweighs the risk to the fetus. Consult a gastroenterologist for advice.
- Breastfeeding: While rabeprazole’s presence in breast milk is uncertain, it’s best to avoid its use during breastfeeding. Omeprazole or pantoprazole are generally preferred if a PPI is required.
Drug Profile Summary
- Mechanism of Action: Inhibits H+/K+ ATPase in gastric parietal cells, reducing acid secretion.
- Side Effects: Common: Headache, diarrhea, abdominal pain. Serious: Hypomagnesemia, bone fractures, drug-induced lupus.
- Contraindications: Hypersensitivity, concomitant use of rilpivirine.
- Drug Interactions: Methotrexate, digoxin, warfarin, clopidogrel, ketoconazole, atazanavir. Consult a drug interaction checker.
- Pregnancy & Breastfeeding: Use with caution only if potential benefits outweigh risks.
- Dosage: GERD: 20 mg once daily. Duodenal ulcers: 20 mg once daily. H. pylori: 20 mg twice daily for 7 days (with antibiotics). Zollinger-Ellison Syndrome: Initial 60 mg/day, adjusted as needed.
- Monitoring Parameters: Magnesium levels (long-term use), signs of infection, symptoms of lupus.
Popular Combinations
Rabeprazole is often combined with antibiotics (amoxicillin and clarithromycin) for H. pylori eradication.
Precautions
Standard precautions apply. Pre-existing medical conditions, particularly involving the liver and kidneys, should be considered. Patients should be monitored for side effects. Patients on long-term therapy should be monitored for vitamin B12 deficiency. Caution advised in patients with osteoporosis or risk factors for fractures.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Rabeprazole?
A: The standard adult dose for GERD and duodenal ulcers is 20 mg once daily. For H. pylori eradication, it’s 20 mg twice daily with antibiotics. Dosing varies for other conditions. Pediatric and special population doses are mentioned in the Dosage section.
Q2: How long does it take for Rabeprazole to work?
A: Relief of symptoms may occur within a few days, but complete healing may take several weeks depending on the condition being treated.
Q3: What are the common side effects of Rabeprazole?
A: Common side effects include headache, diarrhea, abdominal pain, nausea, and constipation.
Q4: Can Rabeprazole be taken during pregnancy?
A: Use with caution if benefits outweigh risks. Discuss with a gastroenterologist.
Q5: Can I take Rabeprazole with other medications?
A: Rabeprazole has significant drug interactions. Always inform your doctor about all other medications you are taking, including OTC drugs and supplements.
Q6: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it is almost time for your next dose. Do not take two doses at the same time.
Q7: Can Rabeprazole be crushed or chewed?
A: No, Rabeprazole tablets and capsules should be swallowed whole. Do not crush, chew, or break them, as this interferes with the delayed-release mechanism.
Q8: What is the difference between Rabeprazole and other PPIs?
A: Rabeprazole, like other PPIs, inhibits acid production, but subtle differences in pharmacokinetics and potential drug interactions exist. Consult a specialist.
Q9: Can Rabeprazole be used long-term?
A: Yes, but long-term use can increase the risk of certain side effects like hypomagnesemia, bone fractures, and fundic gland polyps. Regular monitoring is necessary.
Q10: Is Rabeprazole safe for children?
A: Rabeprazole is approved for use in children over 1 for GERD and over 12 for some other conditions. Always consult a pediatrician for appropriate dosing and monitoring in children.
