Rabeprazole sodium tablets contain rabeprazole. It belongs to a class of medicines called proton pump inhibitors. They act by reducing the amount of acid made by the stomach.
Indications and Usage
- Active duodenal ulcer
- Active benign gastric ulcer
- Symptomatic erosive or ulcerative gastroesophageal reflux disease (GERD)
- Gastroesophageal reflux disease long-term management (GERD maintenance)
- Symptomatic treatment of moderate to very severe gastroesophageal reflux disease (symptomatic GORD)
- Zollinger-Ellison syndrome
- In eradication of Helicobacter pylori in patients with peptic ulcer disease
Mechanism of Action:Rabeprazole sodium belongs to the class of anti-secretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or H2 histamine antagonist properties, but suppress gastric acid secretion by the specific inhibition of the H+/K+-ATPase enzyme (the acid or proton pump) The effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.
Pharmacodynamics Effects:After oral administration of a 20 mg dose of rabeprazole sodium the onset of the anti-secretory effect occurs within one hour, with the maximum effect occurring within two to four hours. Inhibition of basal and food stimulated acid secretion 23 hours after the first dose of rabeprazole sodium are 69% and 82% respectively and the duration of inhibition lasts up to 48 hours. The inhibitory effect of rabeprazole sodium on acid secretion increases slightly with repeated once-daily dosing, achieving steady state inhibition after three days.
Pharmacokinetic properties:Absorption: Absolute bioavailability for a 20 mg oral tablet of rabeprazole (compared with intravenous administration) is approximately 52%. When rabeprazole sodium tablets are administered with a high fat meal, Tmax is variable; which concomitant food intake may delay the absorption up to 4 hours or longer. However, the Cmax and the extent of rabeprazole absorption (AUC) are not significantly altered. Thus, rabeprazole sodium tablets may be taken without regard to timing of meals.
Distribution: Rabeprazole is 96.3% bound to human plasma proteins.
Metabolism: Rabeprazole is extensively metabolized. A significant portion of rabeprazole is metabolized via systemic nonenzymatic reduction to a thioether compound. Rabeprazole is also metabolized to sulphone and desmethyl compounds via CYP450 in the liver. The thioether and sulphone are the primary metabolites measured in human plasma. These metabolites were not observed to have significant antisecretory activity.'In vitro' studies have demonstrated that rabeprazole is metabolized in the liver primarily by CYP450 3A (CYP3A) to a sulphone metabolite and CYP450 2C19 (CYP2C19) (CYP2C19) to desmethylrabeprazole.
Elimination: Following a single 20 mg oral dose of rabeprazole, approximately 90% of the drug was eliminated in the urine, primarily as thioether carboxylic acid; its glucuronide, and mercapturic acid metabolites. The remainder of the dose was recovered in the faeces. Total recovery of radioactivity was 99.8%. No unchanged rabeprazole was recovered in the urine or faeces.
Rabeprazole decreases the concentration of ketoconazole in the plasma (in 33%), increases the concentration of digoxin (in 22%), and does not interact with liquid antacids. Rabeprazole is compatible with any medicine metabolized by the CYP450 (theophylline, warfarin, diazepam, phenytoin).
Pregnancy, breast-feeding and fertility: If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.
Warning & Precautions
Children : Rabeprazole should not be given to children as there is no experience with Rabeprazole in children.