Rabeprazole Sodium

Rabeprazole sodium (Aciphex) is a drug used to treat gastroesophageal reflux disease, or GERD, which is a common digestive problem. In GERD, acid from the stomach flows backward into the esophagus, and irriatates the lining of the esophagus. A muscle usually keeps stomach acid from flowing back into the esophagus, but in GERD, this muscle allows acid from the stomach into the esophagus.



A peptic ulcer is a sore in the stomach or small intestine. It happens when the acid and enzymes that help break down food damage the lining of the stomach or intestine. Ulcers usually affect people who are 25 to 64 years of age. The two main causes are a bacteria called Helicobacter pylori and anti-inflammatory pain medicines like aspirin, ibuprofen (Motrin or Advil), or naproxen (Aleve and others in prescription strengths). Steroids and medicines for osteoporosis also may cause ulcers.



Drug Info

 * Brand name = Aciphex
 * Active ingredient = rabeprazole sodium
 * Strength = 20 mg
 * Dosage = Delayed-release tablets
 * Company = Eisai Inc.
 * Availability = Prescription only
 * Approval date= August 19, 1999

Uses


Rabeprazole is used for:

1. short-term healing of a gradual breakdown (erosion) or sore (ulceration) in the esophagus which may be caused by the backward flow of gastric acid from the stomach into the esophagus (gastroesophageal reflux disease or GERD);

2. maintenance of healing of erosive or ulcerative GERD;

3. treatment of daytime and nighttime heartburn and other symptoms associated with GERD;

4. short-term (up to 4 weeks) healing of an ulcer in the duodenum;

5. elimination of Helicobacter pylori, in combination with amoxicillin and clarithromycin, to reduce the risk of duodenal ulcer recurrence in patients with a current duodenal ulcer or a duodenal ulcer in the past 5 years;

6. medical conditions that result in the body secreting too much acid, including Zollinger-Ellison syndrome.

How It Works
Acid is secreted in the stomach by a type of cell called the parietal cell. There is an enzyme pump (called the H+/K+ ATPase pump) on the side of this cell closest to the stomach lining that pumps acid into the stomach. This is known as the proton pump. The class of drugs to which rabeprazole belongs inhibits this pump. This is why they're called proton-pump inhibitors.

Specifically, rabeprazole blocks the final step in the acid secretion. In contrast to the other PPIs, rabeprazole forms a partially reversible bond with the proton pump. It also works at a broader range of stomach pH. For these reasons, it may work for longer than other PPIs.

Complications
There have been some studies that suggest an increased risk of some respiratory infections (eg. community aquired pneumonia) and Clostridium difficile (an organism causing colitis, an inflammation of the bowel) in people taking proton-pump inhibitors (the class of drug that rabeprazole is in). Also, there may an increased risk of hip fracture with prolonged use of proton pump inhibitors. All of these studies have been criticized by some experts for having a flawed study design, so it isn't clear whether the results are meaningful.

Interactions
Proton-pump inhibitors (PPIs) in general may inhibit the absorption of drugs such as:
 * some antifungals, such as griseofulvin (Grisactin), ketoconazole (Nizoral), itraconazole (Sporanox)
 * iron salts
 * vitamin B12
 * cefpodoxime (Vantin)
 * enoxacin (Penetrex).

PPIs are metabolized (broken down) to varying degrees by an enzyme system in the liver called the cytochrome P450 system. They may speed up or slow down the metabolism of other drugs by increasing or decreasing the effects of the cytochrome P450 enzymes. This is important in patients taking medications in which a small difference in dose can be important to its safety, such as:
 * diazepam (Valium)
 * phenytoin (Dilantin)
 * warfarin (Clinical:Coumadin (WARFARIN SODIUM) coumadin (WARFARIN SODIUM)|Coumadin).

Rabeprazole is less likely to have some of these interactions as compared to some other drugs in the proton-pump inhibitor class. Still, possible interactions need to be kept in mind.

Precautions

 * Rabeprazole does not work for everyone. Improvement in symptoms does not prevent other stomach-related medical conditions.
 * Rabeprazole should be used with caution in patients with severe liver impairment.
 * Rabeprazole is a pregnancy category B drug, meaning there are no studies to determine whether it is safe in pregnancy.
 * It is unknown whether rabeprazole is distributed in breast milk; therefore, depending on the circumstances, either breast feeding or the drug should be discontinued.

Contraindications

 * Rabeprazole is contraindicated for use in any patient that is sensitive to any of its active or inactive ingredients.

Side Effects
This is not a complete list of side effects reported with rabeprazole.

Rabeprazole is generally well tolerated. Side effects affect less than 5% of individuals taking drugs of this class. Some of the more common side effects are:


 * headache
 * diarrhea
 * abdominal pain
 * nausea

How Rabeprazole is Taken

 * Rabeprazole can be taken without regard to meals, but the manufacturer suggests taking it after the morning meal in patients with duodenal ulcer.
 * Tablets should be swallowed whole, without crushing or chewing.

Alternatives
Other medical alternatives to treatment of GERD and ulcers include:


 * H2 blockers (such as ranitidine): H2 blockers are less expensive than PPIs, but PPIs do a better job of suppressing the acid in the stomach that causes the problem. PPIs also provide faster healing rates and better relief of symptoms.


 * Other PPIs: These include omeprazole (Prilosec), lansoprazole (Prevacid) , pantoprazole (Clinical:Protonix (pantoprazole sodium)|Protonix), and esomeprazole (Nexium).

Research Studies
Nocturnal gastric acid breakthrough during the administration of rabeprazole and ranitidine in Helicobacter pylori-negative subjects: effects of different regimens

Comparison of rabeprazole 20mg vs. omeprazole 20mg in the treatment of active gastric ulcer- a European multicenter study

Maintenance treatment of gastroesophageal reflux disease: An evaluation of continuous and on-demand therapy with rabeprazole 20 mg.

Efficacy of rabeprazole in the treatment of symptomatic gastroesophageal reflux disease.

Other Resources
Lexi-Comp, 12th ed.