<p>Decreased digoxin (tablets) and verapamil absorption with antineoplastic regimens. Increased etoposide serum levels with vincristine. Increased toxicity when ganciclovir given with, immediately before or after vincristine. Reduced vincristine metabolism with miconazole. Increased neurotoxicity with isoniazid, itraconazole, voriconazole, posaconazole and nifedipine. Decreased immune response when used concurrently with vaccines. Increased myelotoxicity with zidovudine. Increased risk of thromboembolic complications with tamoxifen. Increased risk of ototoxicity with ototoxic drugs (e.g. platinum-containing antineoplastic agents). Possible risk of earlier onset and/or increased severity of adverse effects with macrolides. Possible increase in vincristine levels with aprepitant. Possible decrease in antiepileptic levels with vincristine, monitor serum antiepileptic levels and effectiveness of chemotherapy.</p>