Rabeprazole 20 mg
MECHANISM OF ACTION
Rabeprazole belongs to a class of antisecretory compounds (substituted benzimidazole proton-pump inhibitors) that do not exhibit anticholinergic or histamine H 2 – receptor antagonist properties, but suppress gastric acid secretion by inhibiting the gastric H + , K + ATPase at the secretory surface of the gastric parietal cell. Because this enzyme is regarded as the acid (proton) pump within the parietal cell, rabeprazole has been characterized as a gastric proton-pump inhibitor. Rabeprazole blocks the final step of gastric acid secretion.
In gastric parietal cells, rabeprazole is protonated, accumulates, and is transformed to an active sulfenamide. When studied in vitro, rabeprazole is chemically activated at pH 1.2 with a half-life of 78 seconds. It inhibits acid transport in porcine gastric vesicles with a half-life of 90 seconds.
Antisecretory Activity The anti-secretory effect begins within one hour after oral administration of 20 mg rabeprazole . The median inhibitory effect of rabeprazole on 24-hour gastric acidity is 88% of maximal after the first dose. Rabeprazole 20 mg inhibits basal and peptone meal-stimulated acid secretion versus placebo by 86% and 95%, respectively, and increases the percent of a 24-hour period that the gastric pH>3 from 10% to 65%. This relatively prolonged pharmacodynamic action compared to the short pharmacokinetic half-life (1-2 hours) reflects the sustained inactivation of the H + , K + ATPase.
Pharmacodynamic studies show, rabeprazole at 10 mg, 20 mg and 40 mg doses significantly decreases intragastric acidity. The ability to decrease the intragastric acid is dose-related.
Effects on Esophageal Acid Exposure In patients with gastroesophageal reflux disease (GERD) and moderate to severe esophageal acid exposure, Rabeprazole 20 mg and 40 mg per day decreased 24-hour esophageal acid exposure. After seven days of treatment, the percentage of time that esophageal pH<4 decreased from baselines of 24.7% for 20 mg and 23.7% for 40 mg, to 5.1% and 2.0%, respectively. Normalization of 24-hour intraesophageal acid exposure was correlated to gastric pH>4 for at least 35% of the 24-hour period; this level was achieved in 90% of subjects receiving rabeprazole 20 mg and in 100% of subjects receiving rabeprazole 40 mg. With rabeprazole 20 mg and 40 mg per day, significant effects on gastric and esophageal pH were noted after one day of treatment, and more pronounced after seven days of treatment.
i.) Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD) AMALGARD is indicated for short-term (4 to 8 weeks) treatment in the healing and symptomatic relief of erosive or ulcerative gastropsophageal reflux disease (GERD). For those patients who have not healed after 8 weeks of treatment, an additional 8-week course of AMALGARD may be considered.
ii.) Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD) AMALGARD is indicated for maintaining healing and reduction in relapse rates of heartburn symptoms in patients with erosive or ulcerative gastroesophageal reflux disease (GERD Maintenance). Controlled studies do not extend beyond 12 months.
iii.) Treatment of Symptomatic Gastroesophageal Reflux Disease (GERD) AMALGARD is indicated in adults and adolescents 12 years of age and above for the treatment of daytime and nighttime heartburn and other symptoms associated with GERD.
iv.) Healing of Duodenal Ulcers AMALGARD is indicated for short-term (up to four weeks) treatment in the healing and symptomatic relief of duodenal ulcers. Most patients heal within four weeks.
v.) Treatment of Pathological Hypersecretory Conditions, Including Zollinger-Ellison Syndrome AMALGARD is indicated for the long-term treatment of pathological hypersecretory conditions, including Zollinger-Ellison syndrome.
DOSAGE AND ADMINISTRATION
AMALGARD tablets should be swallowed whole. The tablets should not be chewed, crushed or split.
AMALGARD can be taken with or without food.
Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD) The recommended adult oral dose is one tablet AMALGARD 20 mg to be taken once daily for four to eight weeks. For those patients who have not healed after 8 weeks of treatment, an additional 8-week course of AMALGARD may be considered.
Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERDMaintenance)
The recommended adult oral dose is one tablet of AMALGARD 20 mg to be taken once daily.
Treatment of Symptomatic Gastroesophageal Reflux Disease (GERD)
The recommended adult oral dose is one tablet of AMALGARD 20 mg to be taken once daily for 4 weeks. If symptoms do not resolve completely after 4 weeks, an additional course of treatment may be considered.
Healing of Duodenal Ulcers
The recommended adult oral dose is one tablet of AMALGARD 20 mg to be taken once daily after the morning meal for a period up to four weeks. Most patients with duodenal ulcer heal within four weeks. A few patients may require additional therapy to achieve healing.
Treatment of Pathological Hypersecretory Conditions Including Zollinger-Ellison Syndrome
The dosage of AMALGARD in patients with pathologic hypersecretory conditions varies with the individual patient. The recommended adult oral starting dose is 60 mg once a day. Doses should be adjusted to individual patient needs and should continue for as long as clinically indicated. Some patients may require divided doses. Doses up to 100 mg QD and 60 mg BID have been administered. Some patients with Zollinger-Ellison syndrome have been treated continuously with rabeprazole for up to one year.
Short-term Treatment of Gastroesophageal Reflux Disease (GERD)in Adolescent Patients 12 years of Age and Above
The recommended oral dose for adolescents 12 years and above is one tablet of AMALGARD 20 mg once daily for up to 8 weeks.
Elderly, Renal and Hepatic Impaired Patients
No dosage adjustment is necessary in elderly patients, in patients with renal disease or in patients with mild to moderate hepatic impairment. Administration of rabeprazole to patients with mild to moderate liver impairment resulted in increased exposure and decreased elimination. Due to the lack of clinical data on rabeprazole in patients with severe hepatic impairment, caution should be exercised in those patients.