Rabeprazole, sold under the brand name Aciphex, among others, is a medication that decreases stomach acid. It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and excess stomach acid production such as in Zollinger–Ellison syndrome. It may also be used in combination with other medications to treat Helicobacter pylori. Effectiveness is similar to other proton pump inhibitors (PPIs). It is taken by mouth.Common side effects include constipation, feeling weak, and throat inflammation. Serious side effects may include osteoporosis, low blood magnesium, Clostridium difficile infection, and pneumonia. Use in pregnancy and breastfeeding is of unclear safety. It works by blocking H+/K+-ATPase in the parietal cells of the stomach.Rabeprazole was patented in 1986, and approved for medical use in 1997. It is available as a generic medication. In 2017, it was the 279th most commonly prescribed medication in the United States, with more than one million prescriptions. Medical uses
Rabeprazole, like other proton pump inhibitors such as omeprazole, is used for the purposes of gastric acid suppression. This effect is beneficial for the treatment and prevention of conditions in which gastric acid directly worsens symptoms, such as duodenal and gastric ulcers. In the setting of gastroesophageal reflux disease (GERD), whose pathophysiology is characterized by prolonged exposure to gastric acid in the esophagus (often due to changes in stomach and/or esophagus anatomy, such as those induced by abdominal obesity), acid suppression can provide symptomatic relief.
Avoiding rabeprazole during breastfeeding confers to lowest possible risk. Geriatrics
Advanced age does not appear to clinically impact rabeprazoles metabolism. However, elevations in the maximum plasma concentration and the total drug exposure (area under the curve, AUC) have occurred. Japanese ancestry
In a study on rabeprazoles pharmacokinetics, the AUC was elevated by approximately 50–60% in men of Japanese ancestry compared to men in the United States. See the pharmacogenetics section below for a pharmacogenetic explanation of these findings. Kidney or liver problems
In people that have kidney or liver problems, these problems do not appear to affect rabeprazoles metabolism in a clinically meaningful way. This includes individuals on dialysis for kidney problems. Severe liver problems like cirrhosis of the liver do affect rabeprazoles elimination half-life, but not to a degree of dangerous accumulation. In a review of patients taking rabeprazole while having end-stage kidney disease and mild-to-moderate severity, chronic compensated cirrhosis of the liver, the alteration in rabeprazoles metabolism was not clinically meaningful. Contraindications
Rabeprazole is contraindicated in the following populations and situations:
people with a known hypersensitivity to rabeprazole, substituted benzimidazoles (which are chemically similar to rabeprazole, like omeprazole), or any other component of the capsule formulation (e.g. certain dyes)
concurrent use of rilpivirine, a medication used to treat HIV infection

Hypersensitivity
Syndrome
An allergy to a PPI like rabeprazole may take the form of type I hypersensitivity or delayed hypersensitivity reactions. A selective (pattern C—see below for a discussion of cross-reactivity patterns) type I hypersensitivity reaction to rabeprazole resulting in anaphylaxis has been reported, as well as several whole group hypersentivities.