Rare instances of rabeprazole-induced liver injury (also known as hepatotoxicity) have been reported. Characteristic proton-pump inhibitor hepatoxicity usually occurs within the first four weeks of starting the medication.Rabeprazole is associated with elevated serum gastrin levels, which are thought to be dependent upon the degree of CYP2C19 metabolism the drug undergoes. In comparison, rabeprazole is not as significantly metabolized by this enzyme compared to other medications in the same class, like omeprazole. Elevated serum gastrin may be associated with gastric cancer.Acid suppression via rabeprazole can decrease the absorption of vitamin B12 and magnesium, leading to deficiency.Very serious side effects have been reported in people taking rabeprazole, but these effects have not been "correlated directly" with the use of rabeprazole. These include Stevens–Johnson syndrome, serious hematological abnormalities, coma, and death. Other possible side effects, common to other PPIs medications in the same class, include bone fractures due to osteoporosis and serious infections with Clostridium difficile. Overdose
No signs and symptoms have been reported in overdoses of rabeprazole up to 80 mg, but case examples are limited. Notably, rabeprazole has been used in higher doses for the treatment of hypersecretory conditions like Zollinger-Ellison syndrome (up to 120 mg daily).Animal experiments with ultra-high doses of rabeprazole have demonstrated lethality through unknown mechanisms. The lethal overdose syndrome in animals is characterized by convulsion and coma. Interactions
Drug-drug interactions
Rabeprazole does not interfere with the plasma concentration of drugs that are also metabolized by the same enzymes (i.e. CYP2C19) that it is metabolized by.
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.