Rabeprazole Sodium (Page 3 of 9)

6.2 Postmarketing Experience

The following adverse reactions have been identified during post approval use of rabeprazole. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:

Blood and Lymphatic System Disorders: agranulocytosis, hemolytic anemia, leukopenia, pancytopenia, thrombocytopenia

Ear and Labyrinth Disorders: vertigo

Eye Disorders: blurred vision

Gastrointestinal Disorders: fundic gland polyps

General Disorders and Administration Site Conditions: sudden death

Hepatobiliary Disorders: jaundice

Immune System Disorders: anaphylaxis, angioedema, systemic lupus erythematosus, Stevens-Johnson syndrome, toxic epidermal necrolysis (some fatal)

Infections and Infestations: Clostridium difficile -associated diarrhea

Investigations: Increases in prothrombin time/INR (in patients treated with concomitant warfarin), TSH elevations

Metabolism and Nutrition Disorders: hyperammonemia, hypomagnesemia

Musculoskeletal System Disorders: bone fracture, rhabdomyolysis

Nervous System Disorders: coma

Psychiatric Disorders: delirium, disorientation

Renal and Urinary Disorders: interstitial nephritis

Respiratory, Thoracic and Mediastinal Disorders: interstitial pneumonia

Skin and Subcutaneous Tissue Disorders: severe dermatologic reactions including bullous and other drug eruptions of the skin, cutaneous lupus erythematosus, erythema multiforme

7 DRUG INTERACTIONS

Table 2 includes drugs with clinically important drug interactions and interaction with diagnostics when administered concomitantly with rabeprazole sodium delayed-release tablets and instructions for preventing or managing them.

Consult the labeling of concomitantly used drugs to obtain further information about interactions with PPIs.

Table 2: Clinically Relevant Interactions Affecting Drugs Co-Administered with Rabeprazole sodium delayed-release tablets and Interactions with Diagnostics

Antiretrovirals
Clinical Impact:	The effect of PPI on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known. • Decreased exposure of some antiretroviral drugs (e.g., rilpivirine, atazanavir, and nelfinavir) when used concomitantly with rabeprazole may reduce antiviral effect and promote the development of drug resistance. • Increased exposure of other antiretroviral drugs (e.g., saquinavir) when used concomitantly with rabeprazole may increase toxicity . • There are other antiretroviral drugs which do not result in clinically relevant interactions with rabeprazole.
Intervention:	Rilpivirine-containing products: Concomitant use with rabeprazole sodium delayed-release tablets is contraindicated [see Contraindications (4)]. See prescribing information. Atazanavir: See prescribing information for atazanavir for dosing information. Nelfinavir: Avoid concomitant use with rabeprazole sodium delayed-release tablets. See prescribing information for nelfinavir. Saquinavir: See the prescribing information for saquinavir and monitor for potential saquinavir toxicities. Other antiretrovirals: See prescribing information.
Warfarin
Clinical Impact:	Increased INR and prothrombin time in patients receiving PPIs, including rabeprazole, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death [see Warnings and Precautions (5.2)].
Intervention:	Monitor INR and prothrombin time. Dose adjustment of warfarin may be needed to maintain target INR range. See prescribing information for warfarin.
Methotrexate
Clinical Impact:	Concomitant use of rabeprazole with methotrexate (primarily at high dose) may elevate and prolong serum levels of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. No formal drug interaction studies of methotrexate with PPIs have been conducted [see Warnings and Precautions (5.9)].
Intervention:	A temporary withdrawal of rabeprazole sodium delayed-release tablets may be considered in some patients receiving high dose methotrexate administration.
Digoxin
Clinical Impact:	Potential for increased exposure of digoxin [see Clinical Pharmacology (12.3)].
Intervention:	Monitor digoxin concentrations. Dose adjustment of digoxin may be needed to maintain therapeutic drug concentrations. See prescribing information for digoxin.
Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole, itraconazole)
Clinical Impact:	Rabeprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity.
Intervention:	Mycophenolate mofetil (MMF): Co-administration of PPIs in healthy subjects and in transplant patients receiving MMF has been reported to reduce the exposure to the active metabolite, mycophenolic acid (MPA), possibly due to a decrease in MMF solubility at an increased gastric pH. The clinical relevance of reduced MPA exposure on organ rejection has not been established in transplant patients receiving rabeprazole sodium delayed-release tablets and MMF. Use rabeprazole sodium delayed-release tablets with caution in transplant patients receiving MMF. See the prescribing information for other drugs dependent on gastric pH for absorption.
Combination Therapy with Clarithromycin and Amoxicillin
Clinical Impact:	Concomitant administration of clarithromycin with other drugs can lead to serious adverse reactions, including potentially fatal arrhythmias, and are contraindicated. Amoxicillin also has drug interactions.
Intervention:	See Contraindications and Warnings and Precautions in prescribing information for clarithromycin. See Drug Interactions in prescribing information for amoxicillin.

Tacrolimus
Clinical Impact:	Potentially increased exposure of tacrolimus, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19.
Intervention:	Monitor tacrolimus whole blood trough concentrations. Dose adjustment of tacrolimus may be needed to maintain therapeutic drug concentrations. See prescribing information for tacrolimus.
Interactions with Investigations of Neuroendocrine Tumors
Clinical Impact:	Serum chromogranin A (CgA) levels increase secondary to PPI-induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors .
Intervention:	Temporarily stop rabeprazole sodium delayed-release tablets treatment at least 14 days before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g. for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary.
Interaction with Secretin Stimulation Test
Clinical Impact:	Hyper-response in gastrin secretion in response to secretin stimulation test, falsely suggesting gastrinoma .
Intervention:	Temporarily stop treatment with rabeprazole sodium delayed-release tablets at least 14 days before assessing to allow gastrin levels to return to baseline.
False Positive Urine Tests for THC
Clinical Impact:	There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs.
Intervention:	An alternative confirmatory method should be considered to verify positive results.