RiteMED Pantoprazole Drug Interactions

Antiretroviral Drugs: Concomitant use of atazanavir, nelfinavir, rilpivirine, saquinavir or raltegravir with PPIs is not recommended. Pantoprazole is expected to substantially decrease atazanavir, nelfinavir or rilpivirine plasma concentrations and may result in a loss of therapeutic effect and the development of drug resistance. In contrast, coadministration of saquinavir or raltegravir with PPIs is expected to increase saquinavir or raltegravir concentrations, which may increase toxicity and require dose reduction.
pH-dependent Drugs: Pantoprazole can reduce the absorption of drugs where gastric pH is an important determinant of their bioavailability. As with other drugs that decrease intragastric acidity, the absorption of drugs such as ketoconazole, ampicillin esters, atazanavir, iron salts, erlotinib, and mycophenolate mofetil (MMF) may decrease.
Mycophenolate mofetil (MMF): Coadministration of pantoprazole in healthy patients 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 in organ rejection has not been established in transplant patients receiving pantoprazole and MMF.
Drugs Affecting/Metabolized by Hepatic Microsomal Enzymes: Pantoprazole is metabolized in the liver through CYP2C19 and CYP3A4. Drugs known to inhibit CYP2C19 such as fluvoxamine may increase the plasma concentrations of pantoprazole by decreasing the rate of its metabolism. In contrast, drugs known to induce CYP2C19 or CYP3A4 or both (e.g., rifampicin and St. John's Wort) may decrease the plasma concentrations of pantoprazole by increasing the rate of its metabolism.
Warfarin: Increased international normalized ratio (INR) and prothrombin time have been reported in patients receiving PPIs and warfarin concomitantly. Since such increases may lead to abnormal bleeding and even death, patients treated with PPIs and warfarin should be monitored for increases in INR and prothrombin time.
Clopidogrel: Concomitant use of pantoprazole with clopidogrel may reduce exposure to the active metabolite of clopidogrel and decrease platelet inhibitory effects.
Drugs that Cause Hypomagnesemia: Possible increased risk of hypomagnesemia; For patients expected to be on prolonged treatment or who take PPIs with medications such as digoxin or drugs that may cause hypomagnesemia (e.g., loop or thiazide diuretics), physicians may consider monitoring the magnesium levels prior to initiation of PPI treatment and periodically thereafter.
Methotrexate: Concomitant administration of PPIs and methotrexate, primarily at high doses, may elevate and prolong serum levels of methotrexate and/or its metabolite hydroxymethotrexate which may lead to methotrexate toxicity. In high-dose methotrexate administration, a temporary withdrawal of the PPI may be considered in some patients.
Sucralfate: Concomitant administration of pantoprazole with sucralfate resulted in delayed absorption and decreased bioavailability of pantoprazole. It should be administered at least 30 minutes before sucralfate.
Laboratory Interactions: There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs such as pantoprazole. An alternative confirmatory method should be considered to verify positive results.