Basic Information
ID DDInter1350 and DDInter1174
Interaction Oseltamivir may inhibit the renal elimination of methotrexate. The pharmacologic effect and toxicity of methotrexate may be increased, especially in patients receiving high-dose methotrexate. The mechanism is competition for renal tubular secretion.
Management If this combination must be used, European drug product labeling recommends that patients should be monitored for signs and symptoms of methotrexate toxicity; e.g., bone marrow suppression, hepatotoxicity, and nephrotoxicity. Patients should be advised to promptly report symptoms including fever, chills, sore throat, bruising, bleeding, stomatitis, malaise, shortness of breath, lower extremity edema, jaundice, or change in stool or urine color to their physician.
References [1] Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0 [2] Nesher G, Mates M, Zevin S "Effect of caffeine consumption on efficacy of methotrexate in rheumatoid arthritis." Arthritis Rheum 48 (2003): 571-572
Alternative for Oseltamivir J05A
Boceprevir Etravirine Voxilaprevir Ombitasvir Ibalizumab Ledipasvir
Peramivir Indinavir Nelfinavir Zanamivir Grazoprevir
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Alternative for Methotrexate L04A
Diroximel fumarate Rilonacept Efalizumab Inebilizumab Dimethyl fumarate Infliximab
Tacrolimus Teriflunomide Sutimlimab Etanercept Apremilast
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Potential Metabolism Interactions
Substrate-Substrate Interaction：If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction：Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction：Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.