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. .fluvoxaminefluvoxamine will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.fondaparinuxcyclophosphamide 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.heparincyclophosphamide 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.hydroxyureacyclophosphamide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.ifosfamidecyclophosphamide, ifosfamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.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.iloperidoneiloperidone 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.indinavirindinavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.influenza A (H5N1) vaccinecyclophosphamide 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), adjuvantedcyclophosphamide decreases effects of influenza virus vaccine (H5N1), adjuvanted by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.isavuconazonium sulfatecyclophosphamide and isavuconazonium sulfate both decrease immunosuppressive effects; risk of infection. Use Caution/Monitor.istradefyllineistradefylline 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.ketoconazoleketoconazole increases toxicity of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lemborexantlemborexant 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.lenacapavirlenacapavir 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. letermovirletermovir increases levels of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lomustinecyclophosphamide, lomustine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.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.lopinavirlopinavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lumacaftor/ivacaftorlumacaftor/ivacaftor, cyclophosphamide. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .mechlorethaminecyclophosphamide, mechlorethamine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with mechlorethamine may increase the risk of immunosuppression and myelosuppression.mechlorethamine, cyclophosphamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with mechlorethamine may increase the risk of immunosuppression and myelosuppression.meningococcal group B vaccinecyclophosphamide decreases effects of meningococcal group B vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Individuals with altered immunocompetence may have reduced immune responses to the vaccine.mifepristonemifepristone will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.mifepristone will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.mitotanemitotane decreases levels of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.nelfinavirnelfinavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ocrelizumabcyclophosphamide and ocrelizumab both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Coadministration of ocrelizumab with immunosuppressants may increase the risk of immunosuppression.ofatumumab SCofatumumab SC, cyclophosphamide. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Consider the risk of additive immune system effects when coadministering immunosuppressive therapies with coadministration. When switching from therapies with immune effects, take into account the duration and mechanism of action of these therapies when initiating ofatumumab SC.olaparibcyclophosphamide and olaparib both increase pharmacodynamic synergism. Use Caution/Monitor. Coadministration with other other myelosuppressive anticancer agents, including DNA damaging agents, may potentiate and prolongate the myelosuppressive toxicity. pentobarbitalpentobarbital will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.phenobarbitalphenobarbital will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.primidoneprimidone will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.rifampinrifampin will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.rifampin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ritonavirritonavir will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.ritonavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rucaparibrucaparib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.saquinavirsaquinavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.secobarbitalsecobarbital will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.siponimodsiponimod and cyclophosphamide both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.sipuleucel-Tcyclophosphamide decreases effects of sipuleucel-T by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.sodium sulfate/?magnesium sulfate/potassium chloridesodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of cyclophosphamide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.sodium sulfate/potassium sulfate/magnesium sulfatesodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of cyclophosphamide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.sorafenibsorafenib will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.sparsentansparsentan will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Sparsentan (a CYP2B6 inducer) decreases exposure of CYP2B6 substrates and reduces efficacy related to these substrates.stiripentolstiripentol, cyclophosphamide. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP2B6 inhibitor and inducer. Monitor CYP2B6 substrates coadministered with stiripentol for increased or decreased effects. CYP2B6 substrates may require dosage adjustment.stiripentol, cyclophosphamide. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.streptozocincyclophosphamide, streptozocin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.succinylcholinecyclophosphamide increases levels of succinylcholine by decreasing metabolism. Use Caution/Monitor. Neuromuscular blockade may be prolonged because of inhibition of cholinesterase activity. Prolonged respiratory depression with extended periods of apnea may occur. .tecovirimattecovirimat will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.thiotepacyclophosphamide, thiotepa. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.tipranavirtipranavir will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.trastuzumabtrastuzumab, cyclophosphamide. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .trastuzumab deruxtecantrastuzumab deruxtecan, cyclophosphamide. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .ublituximabublituximab and cyclophosphamide both increase immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Owing to potential additive immunosuppressive effects, consider duration of effect and mechanism of action of these therapies if coadministeredvoclosporinvoclosporin, cyclophosphamide. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.Minor (340)abemaciclibcyclophosphamide will increase the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.abirateronecyclophosphamide will increase the level or effect of abiraterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.acalabrutinibcyclophosphamide will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.acetazolamideacetazolamide will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ado-trastuzumab emtansinecyclophosphamide will increase the level or effect of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.alfentanilcyclophosphamide will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.alfuzosincyclophosphamide will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.alpelisibcyclophosphamide will increase the level or effect of alpelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.alprazolamcyclophosphamide will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ambrisentancyclophosphamide will increase the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amiodaronecyclophosphamide will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amlodipinecyclophosphamide will increase the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.anastrozoleanastrozole will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apalutamidecyclophosphamide will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apixabancyclophosphamide will increase the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apomorphinecyclophosphamide will increase the level or effect of apomorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apremilastcyclophosphamide will decrease the level or effect of apremilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aprepitantcyclophosphamide will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aripiprazolecyclophosphamide will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.armodafinilcyclophosphamide will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.artemether/lumefantrinecyclophosphamide will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aspirinaspirin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.astemizolecyclophosphamide will increase the level or effect of astemizole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atazanavircyclophosphamide will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atogepantcyclophosphamide will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atorvastatincyclophosphamide will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.avanafilcyclophosphamide will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.avapritinibcyclophosphamide will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.avatrombopagcyclophosphamide will increase the level or effect of avatrombopag by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.axitinibcyclophosphamide increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.bedaquilinecyclophosphamide will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.benzhydrocodone/acetaminophencyclophosphamide will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.benzphetaminecyclophosphamide will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.bortezomibcyclophosphamide will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.bosentancyclophosphamide will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.bosutinibcyclophosphamide will increase the level or effect of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.brentuximab vedotincyclophosphamide will increase the level or effect of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.brexpiprazolecyclophosphamide will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.brigatinibcyclophosphamide will increase the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.bromocriptinecyclophosphamide will increase the level or effect of bromocriptine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.budesonidecyclophosphamide will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance