Interaction between Entecavir and Acyclovir
Moderate
Excretion
| ID | DDInter647 and DDInter25 |
| Interaction | Coadministration of entecavir with another drug that is also eliminated by active tubular secretion may result in increased plasma concentrations of one or both drugs due to competitive inhibition of transporters in the renal tubules. Drugs (and/or their metabolites) that are thought to undergo active tubular secretion include acyclovir, allopurinol, aminosalicylic acid, cidofovir, cimetidine, creatine, dyphylline, famciclovir, famotidine, flecainide, ganciclovir, levetiracetam, metformin, methotrexate, midodrine, mycophenolic acid, oseltamivir, pralatrexate, probenecid, procainamide, quinidine, ranitidine, tenofovir, triamterene, trimethoprim, valacyclovir, valganciclovir, zalcitabine, zidovudine, and many of the beta-lactam and quinolone antibiotics. |
| Management | Patients receiving entecavir with another drug that undergoes active tubular secretion should be monitored for excessive pharmacologic effects of both drugs, and the dosages adjusted as necessary. |
| References | |
| Alternative for Entecavir |
J05A
More
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| Alternative for Acyclovir |
J05A
More
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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.