Interaction between Omeprazole and Methotrexate
Major
Excretion
| ID | DDInter1340 and DDInter1174 |
| Interaction |
Coadministration with proton pump inhibitors (PPIs) may increase the serum concentrations of methotrexate (MTX) and its potentially active 7-hydroxy metabolite. The proposed mechanism is PPI inhibition of the active tubular secretion of MTX and 7-hydroxymethotrexate via renal H+/K+ ATPase pumps. Inhibition of the breast cancer resistance protein (BCRP)-mediated transport of methotrexate and 7-hydroxymethotrexate by the proton pump inhibitors has also been suggested.
adenocarcinoma
adrenal insufficiency
amenorrhea
amyloidosis
als
anaemia hypochromic
arthritis
psoriatic arthritis
Arthritis bacterial
asthma
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| Management | Proton pump inhibitor therapy should preferably be stopped several days prior to administration of methotrexate. In addition, it is not generally recommended to use proton pump inhibitors with high-dose methotrexate therapy, particularly in the presence of renal impairment. If concomitant use is necessary, clinicians should consider the potential for interaction and closely monitor methotrexate serum levels and toxicity. Use of an H2 antagonist may also be an appropriate alternative. It is not known if the interaction occurs with low, oral doses of methotrexate used to treat rheumatoid arthritis. |
| References | |
| Alternative for Omeprazole |
A02B
|
| Alternative for Methotrexate |
L04A
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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.