Rabeprazole Drug Interactions: What to Avoid and What to Tell Your Doctor

Rabeprazole (AcipHex) affects stomach acid levels and can also interact with liver enzymes that process medications. As a result, it can change the effectiveness or safety of many drugs. This guide walks through the most important drug interactions — from contraindicated combinations to those that simply need monitoring.

How Rabeprazole Causes Drug Interactions

Rabeprazole creates drug interactions in two main ways:

Raising stomach pH. By suppressing acid, rabeprazole makes the stomach less acidic (higher pH). Some medications need an acidic environment to dissolve and be absorbed. If stomach pH is raised, these drugs may not absorb properly.

Inhibiting CYP2C19. Rabeprazole mildly inhibits the liver enzyme CYP2C19, which metabolizes many medications. Inhibiting this enzyme can increase blood levels of some drugs (making them more potent) or decrease the conversion of prodrugs to their active forms.

Contraindicated Combinations: Do NOT Take Together

These combinations are contraindicated — meaning they should not be used together:

Rilpivirine (Edurant, Complera, Odefsey, Juluca): Rabeprazole dramatically reduces rilpivirine absorption by raising stomach pH. This can cause HIV treatment failure and allow the virus to develop resistance. This contraindication applies to ALL proton pump inhibitors.

Nelfinavir (an HIV protease inhibitor): Rabeprazole decreases nelfinavir absorption and also inhibits the conversion of nelfinavir to its active metabolite via CYP2C19. Concomitant use is contraindicated.

Major Interactions: Use With Caution and Monitor Closely

Warfarin (Coumadin): Patients on warfarin who start or stop rabeprazole should have their INR/prothrombin time monitored. Elevated INR has been reported, which can increase bleeding risk. No formal dose adjustment protocol exists — just close monitoring.

Methotrexate: PPIs including rabeprazole may increase serum methotrexate concentrations, increasing the risk of methotrexate toxicity (including bone marrow suppression and kidney damage). Monitor closely in patients on both drugs, especially at high methotrexate doses.

Atazanavir (HIV medication): Co-administration is generally not recommended. PPIs substantially reduce atazanavir blood levels, potentially causing HIV treatment failure. If a PPI is necessary, it should be used with extreme caution and with close HIV virologic monitoring.

Acalabrutinib (cancer drug): Avoid PPIs with acalabrutinib — reduced absorption may decrease efficacy of this cancer treatment. Use antacids or H2 blockers instead.

Moderate Interactions: May Require Monitoring or Dose Adjustment

Clopidogrel (Plavix): Unlike omeprazole, rabeprazole has NOT shown a significant reduction in clopidogrel's antiplatelet effect in clinical studies. The FDA label states no dose adjustment of clopidogrel is necessary with approved rabeprazole doses. However, if you're on clopidogrel, ask your cardiologist about this interaction.

Digoxin: Rabeprazole increases digoxin blood levels by approximately 19–29% by altering its absorption. Monitor digoxin levels and watch for signs of toxicity (nausea, vision changes, irregular heartbeat) in patients on both drugs.

Ketoconazole, itraconazole (antifungals): Rabeprazole reduces the absorption of these antifungals by about 30% by raising stomach pH. Alternative antifungal agents may be needed if you require both.

Mycophenolate mofetil (immune suppressant): PPIs may reduce the absorption of mycophenolate. Transplant patients should have their immunosuppressant levels monitored if starting or stopping a PPI.

Iron supplements: Stomach acid is needed for iron absorption. Rabeprazole reduces iron absorption from supplements. If iron deficiency is a concern, consider monitoring iron levels or separating doses as far apart as possible.

Cannabidiol (CBD): Both CBD and rabeprazole are metabolized by CYP2C19 and can inhibit each other's metabolism. Higher levels of either may result from co-use. Discuss with your doctor if you use CBD products medicinally.

Drug Interactions During H. pylori Triple Therapy

When rabeprazole is used with clarithromycin and amoxicillin for H. pylori treatment, note that clarithromycin has its own significant drug interaction profile. Clarithromycin is a potent CYP3A4 inhibitor and should not be combined with:

Pimozide or cisapride (contraindicated — cardiac arrhythmia risk)

Certain statins (can cause muscle damage)

Warfarin (significantly increases INR)

Always provide your full medication list to your prescriber before starting H. pylori triple therapy.

What to Tell Your Doctor Before Starting Rabeprazole

Before starting rabeprazole, make sure your doctor and pharmacist know about ALL medications you take, including:

All prescription drugs — especially HIV antiretrovirals, blood thinners, immunosuppressants, cancer drugs

Over-the-counter medications — especially iron supplements, antifungal creams taken by mouth, and antacids

Vitamins, minerals, and herbal supplements

CBD or cannabis products

For more on rabeprazole safety, see our guide on rabeprazole side effects. If you're having trouble finding your prescription, medfinder can help locate a pharmacy near you with it in stock.