by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.estrogens esterifiedMinor (1)cyclophosphamide will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.estropipateMinor (1)cyclophosphamide will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.eszopicloneMinor (1)cyclophosphamide will increase the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etanerceptSerious - Use Alternative (1)etanercept, cyclophosphamide. Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. The incidence of noncutaneous solid malignancies may be increased in patients receiving TNF blocking agents with cyclophosphamide. Coadministration is not recommended.ethinylestradiolMinor (1)cyclophosphamide will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ethosuximideMinor (1)cyclophosphamide will increase the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etoposideMinor (1)cyclophosphamide will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etravirineMinor (1)cyclophosphamide will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.everolimusMinor (1)cyclophosphamide will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.exemestaneMinor (1)cyclophosphamide will increase the level or effect of exemestane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fedratinibMonitor Closely (1)fedratinib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.Minor (1)cyclophosphamide will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.felbamateMinor (1)cyclophosphamide will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.felodipineMinor (1)cyclophosphamide will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fenofibrateMinor (1)cyclophosphamide will increase the level or effect of fenofibrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fenofibrate micronizedMinor (1)cyclophosphamide will increase the level or effect of fenofibrate micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fenofibric acidMinor (1)cyclophosphamide will increase the level or effect of fenofibric acid by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fentanylMinor (1)cyclophosphamide will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fentanyl intranasalMinor (1)cyclophosphamide will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fentanyl transdermalMinor (1)cyclophosphamide will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fentanyl transmucosalMinor (1)cyclophosphamide will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fexinidazoleSerious - Use Alternative (2)fexinidazole will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6. fexinidazole will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.finerenoneMinor (1)cyclophosphamide will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fingolimodMonitor Closely (1)cyclophosphamide increases effects of fingolimod by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Concomitant therapy is expected to increase the risk of immunosuppression. Use caution when switching patients from long-acting therapies with immune effects. .flibanserinMinor (1)cyclophosphamide will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.flunisolide inhaledMinor (1)cyclophosphamide will increase the level or effect of flunisolide inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.flurazepamMinor (1)cyclophosphamide will increase the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.flutamideMinor (1)cyclophosphamide will increase the level or effect of flutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fluticasone furoateMinor (1)cyclophosphamide will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fluticasone inhaledMinor (1)cyclophosphamide will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fluvoxamineMonitor Closely (1)fluvoxamine will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.fondaparinuxMonitor Closely (1)cyclophosphamide increases effects of fondaparinux by unknown mechanism. Use Caution/Monitor. Due to potential thrombocytopenic effects of cyclophosphamide, an additive risk of bleeding may be seen in patients receiving concomitant anticoagulants.fosamprenavirMinor (1)cyclophosphamide will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fosaprepitantMinor (1)cyclophosphamide will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fostamatinibMinor (1)cyclophosphamide will increase the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.gefitinibMinor (1)cyclophosphamide will increase the level or effect of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.glasdegibMinor (1)cyclophosphamide will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.glecaprevir/pibrentasvirMinor (1)cyclophosphamide will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.guanfacineMinor (1)cyclophosphamide will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.haloperidolMinor (1)cyclophosphamide will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.heparinMonitor Closely (1)cyclophosphamide increases effects of heparin by unknown mechanism. Use Caution/Monitor. Due to potential thrombocytopenic effects of cyclophosphamide, an additive risk of bleeding may be seen in patients receiving concomitant anticoagulants.hydrochlorothiazideSerious - Use Alternative (1)hydrochlorothiazide increases toxicity of cyclophosphamide by decreasing renal clearance. Avoid or Use Alternate Drug. Increased myelosuppressive effects.hydrocodoneMinor (1)cyclophosphamide will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.hydroxyprogesterone caproate (DSC)Minor (1)cyclophosphamide will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.hydroxyureaMonitor Closely (1)cyclophosphamide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.ibrutinibMinor (1)cyclophosphamide will increase the level or effect of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.idarubicinSerious - Use Alternative (1)cyclophosphamide increases toxicity of idarubicin by Other (see comment). Avoid or Use Alternate Drug. Comment: May increase formation of toxic anthracycline metabolites in heart tissue.idecabtagene vicleucelSerious - Use Alternative (1)cyclophosphamide, idecabtagene vicleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.idelalisibSerious - Use Alternative (1)idelalisib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substratesMinor (1)cyclophosphamide will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ifosfamideMonitor Closely (2)ifosfamide, cyclophosphamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with ifosfamide may increase the risk of immunosuppression and myelosuppression. cyclophosphamide, ifosfamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.Minor (1)cyclophosphamide will increase the level or effect of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.iloperidoneMonitor Closely (1)iloperidone increases levels of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.imatinibMinor (1)cyclophosphamide will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.indinavirMonitor Closely (1)indinavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)cyclophosphamide will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.influenza A (H5N1) vaccineMonitor Closely (1)cyclophosphamide decreases effects of influenza A (H5N1) vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.influenza virus vaccine (H5N1), adjuvantedMonitor Closely (1)cyclophosphamide decreases effects of influenza virus vaccine (H5N1), adjuvanted by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.influenza virus vaccine quadrivalent, adjuvantedSerious - Use Alternative (1)cyclophosphamide decreases effects of influenza virus vaccine quadrivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.influenza virus vaccine trivalent, adjuvantedSerious - Use Alternative (1)cyclophosphamide decreases effects of influenza virus vaccine trivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.irinotecanMinor (1)cyclophosphamide will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.irinotecan liposomalMinor (1)cyclophosphamide will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.isavuconazonium sulfateMonitor Closely (1)cyclophosphamide and isavuconazonium sulfate both decrease immunosuppressive effects; risk of infection. Use Caution/Monitor.Minor (1)cyclophosphamide will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.isosorbide dinitrateMinor (1)cyclophosphamide will increase the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.isosorbide mononitrateMinor (1)cyclophosphamide will increase the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.isradipineMinor (1)cyclophosphamide will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.istradefyllineMonitor Closely (1)istradefylline will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.Minor (1)cyclophosphamide will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.itraconazoleMinor (1)cyclophosphamide will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ivacaftorMinor (1)cyclophosphamide will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ivosidenibMinor (1)cyclophosphamide will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ixabepiloneMinor (1)cyclophosphamide will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ixazomibMinor (1)cyclophosphamide will increase the level or effect of ixazomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ketamineMinor (1)cyclophosphamide will increase the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ketoconazoleMonitor Closely (1)ketoconazole increases toxicity of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lacosamideMinor (1)cyclophosphamide will increase the level or effect of lacosamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lansoprazoleMinor (1)cyclophosphamide will increase the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lapatinibMinor (1)cyclophosphamide will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.larotrectinibMinor (2)larotrectinib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. cyclophosphamide will increase the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lemborexantMonitor Closely (1)lemborexant will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Monitor CYP2B6 substrate for adequate clinical response. Consider increasing the CYP2B6 substrate dose according to specific prescribing recommendations.Minor (1)cyclophosphamide will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lenacapavirMonitor Closely (1)lenacapavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates. letermovirMonitor Closely (1)letermovir increases levels of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.levamlodipineMinor (1)cyclophosphamide will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.levoketoconazoleMinor (1)levoketoconazole will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.levomilnacipranMinor (1)cyclophosphamide will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.levonorgestrel intrauterineMinor (1)cyclophosphamide will increase the level or effect of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.levonorgestrel oralMinor (1)cyclophosphamide will increase the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.linagliptinMinor (1)cyclophosphamide will increase the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lisocabtagene maraleucelSerious - Use Alternative (1)cyclophosphamide, lisocabtagene maraleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.lomitapideMinor (1)cyclophosphamide increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lomustineMonitor Closely (2)lomustine, cyclophosphamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with lomustine may increase the risk of immunosuppression and myelosuppression. cyclophosphamide, lomustine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.lonafarnibSerious - Use Alternative (1)lonafarnib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.Minor (1)cyclophosphamide