Professional Information
Rabeprazole (Systemic)
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USAN:
Rabeprazole
INN:
Rabeprazole
VA CLASSIFICATION
Primary: GA304
Commonly used brand name(s): AcipHex.
Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).
†Not commercially available in Canada.
Category:
Gastric acid pump inhibitor —
antiulcer agent {01}—
Indications
Accepted
Gastroesophageal reflux disease [GERD] (prophylaxis and treatment) —Rabeprazole is indicated for the short-term treatment 4-8 weeks for symptomatic relief and healing of erosive or ulcerative gastroesophageal reflex disease. Rabeprazole may be indicated for an additional 8 weeks of treatment for patients in whom healing has not occurred. Rabeprazole also is indicated to maintain healing of erosive or ulcerative gastroesophageal reflux disease.{01}
Hypersecretory conditions, gastric (treatment) {01}
Zollinger-Ellison syndrome (treatment) {01}—Rabeprazole is indicated for the long-term treatment of pathological hypersecretory conditions, including Zollinger-Ellison syndrome.{01}
Ulcer, duodenal (treatment)—Rabeprazole is indicated for short-term treatment (up to 4 weeks) in the healing and symptomatic relief of patients with active duodenal ulcers.{01}
Pharmacology/Pharmacokinetics
Physicochemical characteristics:
Chemical group—
Substituted benzimidazole{01}
Molecular weight—
381.43{01}
Mechanism of action/Effect:
Rabeprazole is a selective and irreversible proton pump inhibitor. Rabeprazole suppresses gastric acid secretion by specific inhibition of the hydrogen-potassium adenosine triphosphatase (H+, K+-ATPase) enzyme system found at the secretory surface of parietal cells. It inhibits the final transport of hydrogen ions (via exchange with potassium ions) into the gastric lumen. Since the H+, K +-ATPase enzyme system is regarded as the acid (proton) pump of the gastric mucosa, rabeprazole is known as a gastric acid pump inhibitor. Rabeprazole does not have anticholinergic or histamine H2-receptor antagonist properties.{01}
Absorption:
Since rabeprazole is acid-labile, it is administered as a delayed-release tablet so that it can pass through the stomach relatively intact. Once rabeprazole has left the stomach, absorption occurs within 1 hour of administration. The bioavailability is approximately 52%.{01}
Distribution:
Distributed in tissue, particularly gastric parietal cells.{01}
Protein binding:
Very high; approximately 96% bound to human plasma protein.{01}
Biotransformation:
Rabeprazole is extensively metabolized in the liver by the cytochrome P450 enzyme system to 2 main metabolites. These 2 metabolites do not have any significant antisecretory activity.{01}
Elimination
Normal renal function: Approximately 1 to 2 hours{01}
Hepatic function impairment: 2 to 6 hours{01}
Onset of action:
The anti-secretory effect of rabeprazole begins 1 hour following administration.{01}
Time to peak concentration:
Approximately 2 to 5 hours.{01}
Peak serum concentration:
The peak rabeprazole serum concentration is linear over an oral dosage range of 10 to 40 mg{01}
Duration of action:
More than 24 hours. The mean inhibitory effect of rabeprazole on 24–hour gastric acidity is 88% of maximal after the first dose.{01}
Elimination:
Renal—Approximately 90% of the rabeprazole dose is excreted in the urine as metabolites. These metabolites are mainly thioether carboxylic acid (TCA), the glucuronide of TCA, and mercapturic acid. No unchanged rabeprazole is detected in the urine.{01}
Fecal—Approximately 10% as metabolites. No unchanged rabeprazole is detected in the feces.{01}
In dialysis—Rabeprazole is highly protein bound and is not readily dialyzable{01}.
Precautions to Consider
Carcinogenicity/Tumorigenicity
In a 1 to 2 year study of mice receiving a dose of rabeprazole resulting in 1.6 times the human exposure of the recommended doses, increase in tumor occurrence was demonstrated. Another study of 104 weeks in duration in which rabeprazole was administered at doses of up to 60 mg/kg/day in male rats and up to 120 mg/kg/day in female rats, enterochromaffin-like (ECL) cell hyperplasia was observed in both male and female rats. Only the female rats demonstrated ECL carcinoid tumors at all dosage levels (5, 15, 30, 60, and 120 mg/kg/day). The lowest dose tested in the female rats was 0.1 times the human exposure at the recommended rabeprazole dose for gastroesophageal reflux disease (GERD).{01}
Mutagenicity
Some of the mutagenicity tests were positive, while other tests were negative for rabeprazole. The following tests were positive: the Ames test, the Chinese hamster ovary cell forward gene mutation test, and the mouse lymphoma cell forward gene test. The following tests were negative: the in vitro Chinese hamster lung cell chromosome aberration tests, the in vivo mouse micronucleus test, and the in vivo and ex vivo hepatocyte unscheduled DNA synthesis (UDS) tests.{01}
Pregnancy/Reproduction
Fertility—
Fertility studies in rats using a dose resulting in 10 times the human rabeprazole exposure at recommended doses demonstrated no effect on fertility.{01}
Pregnancy—
Adequate and well-controlled studies in human have not been done.{01}
However, no teratogenic effects and impaired fertility were demonstrated at doses up to 13 and 8 times the human exposure at recommended dose for GERD in rats and rabbits, respectively.{01}
FDA Pregnancy Category B{01}
Breast-feeding
It is not known whether rabeprazole is distributed into human milk. However, in lactating rats, levels of rabeprazole were 2 to 7 times higher in milk than in blood. Administration of rabeprazole to rats in late gestation and during lactation at doses 195 times the human dose based on mg/m2 resulted in decreases in body weight gain of the pups. A decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.{01}
Pediatrics
No information is available on the relationship of age to the effects of rabeprazole in pediatric patients. Safety and efficacy have not been established.{01}
Geriatrics
No differences in safety and efficacy were observed in studies of patients over 65 and over 75 years old and younger patients. However, some geriatric patients may be more sensitive to rabeprazole.{01}
Pharmacogenetics
Efficacy and adverse events were comparable between men and women.{01}
Pharmacokinetic studies in healthy Japanese men using different formulations of rabeprazole showed approximately 50 to 60% increase in area under the plasma concentration-time curve (AUC) as compared to data from healthy men in the United States.{01}
Drug interactions and/or related problems
The following drug interactions and/or related problems have been selected on the basis of their potential clinical significance (possible mechanism in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):
Note: Rabeprazole increased gastric pH and has the potential to affect the bioavailability of any medication for which absorption is pH-dependent.{01}
Combinations containing any of the following medications, depending on the amount present, may also interact with this medication.
» Digoxin (rabeprazole may increase gastrointestinal pH; concurrent use with rabeprazole resulted in increase of the serum peak concentration by 29% in normal subjects{01})
» Ketoconazole (rabeprazole may increase gastrointestinal pH; concurrent use with rabeprazole resulted in 30% reduction of bioavailability{01})
Laboratory value alterations
The following have been selected on the basis of their potential clinical significance (possible effect in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):
With physiology/laboratory test values
Alanine aminotransferase (ALT), serum and
Aspartate aminotransferase (AST), serum (values may be increased during therapy; incidence of an increase of 1.25 times baseline value was 0.2% as compared to 0.8% with placebo{01})
Gastrin, serum (median fasting gastrin level increased in a dose-dependent manner in long-term therapy for up to 52 weeks; the median values were within the normal range{01})
Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).
Risk-benefit should be considered when the following medical problems exist
Helicobacter pylori infection (may develop mild or moderate inflammation in the gastric body or mild inflammation in the gastric antrum{01})
Hepatic impairment, mild to moderate (may increase exposure and decrease elimination)
» Hepatic impairment, severe (may increase exposure and decrease elimination; however, caution is recommended in patients with severe hepatic impairment)
Hypersensitivity to rabeprazole or other substituted benzimidazoles
Side/Adverse Effects
Note: Rabeprazole 10 or 20 mg/day for up to 1 year resulted in time- and dose-dependent increase in the incidence of enterochromaffin-like (ECL) cell hyperplasia. However, no patient developed carcinoid tumors or adenomatoid, dysplastic or neoplastic changes of ECL cells in the gastric mucosa.{01}
The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:
Those indicating need for medical attention
Incidence rare
Apnea (breathing interruptions)
convulsions (seizures)
hematologic abnormalities, specifically anemia {01} (unusual tiredness or weakness), agranulocytosis {01} (chills; fever; sore throat; unusual tiredness or weakness)—sometimes fatal
hemolytic anemia {01} (continuing unusual tiredness or weakness), leukopenia or neutropenia {01} (continuing ulcers or sores in mouth), pancytopenia {01} or thrombocytopenia {01} (unusual bleeding or bruising)
hematuria (bloody urine)
hepatitis (yellow eyes or skin)
Those indicating need for medical attention only if they continue or are bothersome
Incidence more frequent
Headache
Incidence less frequent or rare
Asthenia or
malaise ( feeling weak)
constipation
dizziness
dyspepsia (heartburn)
flatulence (gas)
nausea and vomiting
paresthesia ( numbness, tingling, pain , or weakness in hands or feet)
pruritus (itchy skin)
somnolence (sleepiness)
stomach pain
Overdose
For more information on the management of overdose or unintentional ingestion, contact a poison control center (see Poison Control Center Listing).
Clinical effects of overdose
No large overdose with rabeprazole has been reported. There were no clinical signs or symptoms associated with the 7 reported overdoses of up to 80 mg.{01}
Treatment of overdose
There is no specific antidote for rabeprazole. Treatment is essentially symptomatic and supportive. Rabeprazole is not appreciably removed by dialysis.{01}
Patients in whom intentional overdose is confirmed or suspected should be referred for psychiatric consultation.
Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Rabeprazole (Systemic).
In providing consultation, consider advising the patient on the following (» = major clinical significance):
Before using this medication
» Conditions affecting use, especially:
Hypersensitivity to rabeprazole or substituted benzimidazoles products.
Breast-feeding—Distributed into milk of rats in animal studies; may cause potentially serious adverse effects in nursing infants.
Other medications, especially digoxin or ketoconazole.
Proper use of this medication
» Swallowing tablet whole without crushing, breaking, chewing, or splitting
» Compliance with therapy
» Proper dosing
Taking as soon as possible; not taking if almost time for next dose; not doubling doses
» Proper storage
Precautions while using this medication
» Visits to physician to check progress if condition does not improve or worsen at predetermined time period
Side/adverse effects
Signs of potential side effects, especially apnea, convulsions, hematologic abnormalities, hematuria, or hepatitis.
General Dosing Information
Rabeprazole delayed-released tablet should be swallowed whole, and not chewed, crushed, or split.{01}
Symptomatic response to therapy does not preclude the presence of gastric malignancy.{01}
Rabeprazole may be taken with antacid without affecting the plasma rabeprazole concentrations.{01}
Diet/Nutrition
Rabeprazole, when used to treat duodenal ulcers, should be taken after the morning meal.{01}
Oral Dosage Forms
RABEPRAZOLE DELAYED-RELEASE TABLETS
Usual Adult Dose
Gastroesophageal reflux disease (treatment)
Oral, 20 mg once a day for 4 to 8 weeks. May be continued for an additional 8 weeks if necessary.{01}
Gastroesophageal reflux disease (maintenance)
Oral, 20 mg once a day.{01}
Duodenal ulcers (treatment)
Oral, 20 mg once a day after the morning meal for up to 4 weeks. A few patients may require additional therapy beyond the 4 weeks.{01}
Pathological hypersecretory conditions including Zollinger-Ellison Syndrome
Oral, 60 mg once a day, the dosage may be adjusted as needed, and therapy continued for as long as clinically indicated. Dose up to 100 mg once a day or 60 mg twice a day for a period up to 1 year have been used.{01}
Usual pediatric dose
Dosage has not been established.{01}
Usual geriatric dose
See Usual adult dose{01}
Strength(s) usually available
U.S.—
20 mg (Rx) [AcipHex (hydroxypropyl cellulose) (magnesium oxide) (talc) (ferric oxide (yellow))]
Packaging and storage:
Store at 25°C (77°F); excursion permitted to 15 and 30°C (59 and 86°F).{01}
Protect from moisture{01}
Developed: 12/02/1999
References
- Product information: AcipHex™, rabeprazole. Eisai Co., Ltd., Misato, Japan, August, 1999.
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