General Information

In February 2002, the indications for Aciphex were expanded to include the treatment of patients with symptomatic gastroesophageal reflux disease (GERD). Aciphex, a proton pump inhibitor, can now be used for the treatment of daytime and nighttime heartburn and other symptoms associated with GERD.

Individuals with symptomatic GERD often suffer from heartburn, belching and regurgitation (when digestive acid moves back up the esophagus). In contrast to those with erosive GERD, patients with symptomatic GERD do not have evidence of erosion to the esophagus. Heartburn, which affects over 60 million Americans on a monthly basis, is the most common symptom of symptomatic GERD.

Prior to this new indication, Aciphex was approved for the healing of erosive GERD, the maintenance of healed erosive GERD, and the healing of duodenal ulcers. Aciphex is also used for the treatment of pathological hypersecretory conditions, such as Zollinger-Ellison syndrome.

Clinical Results

Two multicenter, double-blind, placebo-controlled trials evaluating Aciphex were conducted in the United States. The trials included 316 subjects with daytime and nighttime heartburn who did not have esophageal erosions. Subjects received either Aciphex 10 mg, Aciphex 20 mg or placebo, and they were given a diary to keep track of their GERD symptoms. Subjects returned for assessment at week two and four.

Trials results demonstrated that the percentage of heartburn-free daytime and/or nighttime periods was significantly greater with Aciphex 20 mg than with placebo. Additionally, daily antacid consumption was significantly reduced with Aciphex versus placebo over four weeks of treatment.

Side Effects

Treatment with rabeprazole has been generally well tolerated in both short-term and long-term trials.

In the two US trials, the most common adverse events potentially related to Aciphex 20 mg (and occurring at greater than 2% frequency) were abdominal pain, diarrhea and headache.

Mechanism of Action

Rabeprazole belongs to a class of antisecretory compounds (substituted benzimidazole proton-pump inhibitors) that do not exhibit anticholinergic or histamine H2-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. (from Aciphex Prescribing Information)

Additional Information

Aciphex is referred to as Pariet outside of the United States. Aciphex was discovered and developed by Eisai, and it is co-marketed in the United States by Eisai and Janssen Pharmaceutica.

For additional information on Aciphex, please visit the product web site at www.aciphex.com.

Individuals interested in learning more about GERD can obtain information from the National Institute of Diabetes and Digestive and Kidney Diseases.