Minor/Significance Unknown.ruxolitinib topicalMinor (1)cyclophosphamide will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.salmeterolMinor (1)cyclophosphamide will increase the level or effect of salmeterol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.saquinavirMonitor Closely (1)saquinavir 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 saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.saxagliptinMinor (1)cyclophosphamide will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.secobarbitalMonitor Closely (1)secobarbital will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.selpercatinibMinor (1)cyclophosphamide will increase the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sildenafilMinor (1)cyclophosphamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.simvastatinMinor (1)cyclophosphamide will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.siponimodMonitor Closely (1)siponimod 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.Minor (1)cyclophosphamide will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sipuleucel-TMonitor Closely (1)cyclophosphamide decreases effects of sipuleucel-T by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.sirolimusMinor (1)cyclophosphamide will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sodium sulfate/?magnesium sulfate/potassium chlorideMonitor Closely (1)sodium 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 sulfateMonitor Closely (1)sodium 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.sofosbuvir/velpatasvirMinor (1)cyclophosphamide will increase the level or effect of sofosbuvir/velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.solifenacinMinor (1)cyclophosphamide will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sonidegibMinor (1)cyclophosphamide will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sorafenibMonitor Closely (1)sorafenib will increase the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.Minor (1)cyclophosphamide will increase the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sparsentanMonitor Closely (1)sparsentan 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.stiripentolMonitor Closely (2)stiripentol, 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.Minor (1)cyclophosphamide will increase the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.streptozocinMonitor Closely (1)cyclophosphamide, streptozocin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.succinylcholineMonitor Closely (1)cyclophosphamide 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. .sufentanilMinor (1)cyclophosphamide will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sufentanil SLMinor (1)cyclophosphamide will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sunitinibMinor (1)cyclophosphamide will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.suvorexantMinor (1)cyclophosphamide will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tacrolimusMinor (1)cyclophosphamide will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tacrolimus ointmentMinor (1)cyclophosphamide will increase the level or effect of tacrolimus ointment by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tadalafilMinor (1)cyclophosphamide will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tamoxifenMinor (1)cyclophosphamide decreases effects of tamoxifen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tamsulosinMinor (1)cyclophosphamide will increase the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tasimelteonMinor (1)cyclophosphamide will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tazemetostatMinor (1)cyclophosphamide will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tecovirimatMonitor Closely (1)tecovirimat 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.temsirolimusMinor (1)cyclophosphamide will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.teniposideMinor (1)cyclophosphamide will increase the level or effect of teniposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tetracyclineMinor (1)cyclophosphamide will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tezacaftorMinor (1)cyclophosphamide will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.theophyllineMinor (1)cyclophosphamide will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.thiotepaMonitor Closely (1)cyclophosphamide, thiotepa. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive myelosuppression.tiagabineMinor (1)cyclophosphamide will increase the level or effect of tiagabine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ticagrelorMinor (1)cyclophosphamide will increase the level or effect of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ticlopidineMinor (1)cyclophosphamide will increase the level or effect of ticlopidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tinidazoleMinor (1)cyclophosphamide will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tipranavirMonitor Closely (1)tipranavir 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 tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tisagenlecleucelSerious - Use Alternative (1)cyclophosphamide, tisagenlecleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.tofacitinibSerious - Use Alternative (1)cyclophosphamide, tofacitinib. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.Minor (1)cyclophosphamide will increase the level or effect of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tolterodineMinor (1)cyclophosphamide will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tolvaptanMinor (1)cyclophosphamide will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.toremifeneMinor (1)cyclophosphamide will increase the level or effect of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.trabectedinMinor (1)cyclophosphamide will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tramadolMinor (1)cyclophosphamide will increase the level or effect of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.trastuzumabMonitor Closely (1)trastuzumab, 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 deruxtecanMonitor Closely (1)trastuzumab 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. .trazodoneMinor (1)cyclophosphamide will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.triazolamMinor (1)cyclophosphamide will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.trimethoprimMinor (1)cyclophosphamide will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.trimipramineMinor (1)cyclophosphamide will increase the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.tucatinibSerious - Use Alternative (1)tucatinib will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.ublituximabMonitor Closely (1)ublituximab 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 coadministeredubrogepantMinor (1)cyclophosphamide will increase the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ulipristalMinor (1)cyclophosphamide will increase the level or effect of ulipristal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.umeclidinium bromide/vilanterol inhaledMinor (1)cyclophosphamide will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.upadacitinibMinor (1)cyclophosphamide will increase the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.valbenazineMinor (1)cyclophosphamide will increase the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vandetanibMinor (1)cyclophosphamide will increase the level or effect of vandetanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vardenafilMinor (1)cyclophosphamide will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.velpatasvirMinor (1)cyclophosphamide will increase the level or effect of velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vemurafenibMinor (1)cyclophosphamide will increase the level or effect of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.venetoclaxMinor (1)cyclophosphamide will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.venlafaxineMinor (1)cyclophosphamide will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.verapamilMinor (1)cyclophosphamide will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vilanterol/fluticasone furoate inhaledMinor (1)cyclophosphamide will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vilazodoneMinor (1)cyclophosphamide will increase the level or effect of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vinblastineMinor (1)cyclophosphamide will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vincristineMinor (1)cyclophosphamide will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vincristine liposomalMinor (1)cyclophosphamide will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vinorelbineMinor (1)cyclophosphamide will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.voclosporinMonitor Closely (1)voclosporin, 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.vorapaxarMinor (1)cyclophosphamide will increase the level or effect of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.voriconazoleMinor (1)cyclophosphamide will increase the level or effect of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vortioxetineMinor (1)cyclophosphamide will increase the level or effect of vortioxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.voxelotorSerious - Use Alternative (1)voxelotor will increase the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.voxilaprevirMinor (1)cyclophosphamide will increase the level or effect of voxilaprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.warfarinMinor (1)warfarin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.zanubrutinibMinor (1)cyclophosphamide will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.zolpidemMinor (1)cyclophosphamide will increase the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.zonisamideMinor (1)cyclophosphamide will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. >10% Alopecia (40-60%) Nausea and vomiting GI toxicity Leukopenia Amenorrhea Sterility 1-10% Facial flushing Headache Rash Syndrome of inappropriate antidiuretic hormone secretion (SIADH) Nasal congestion Frequency Not Defined Cardiomyopathy, CHF (high dose) Stevens-Johnson syndrome Toxic epidermal necrolysis (rare) Hemorrhagic cystitis Azoospermia Oligozoospermia Interstitial pneumonia Infectious disease Secondary malignancies: Urinary bladder, myeloproliferative, lymphoproliferative Frequency Not Defined Neutropenia Fever Nausea Vomiting Anorexia Abdominal discomfort or pain Diarrhea Hemorrhagic colitis Oral mucosal ulceration Jaundice Alopecia Skin rash Pigmentation of skin and changes in nails Postmarketing Reports Cardiac: Cardiac arrest, ventricular fibrillation, ventricular tachycardia, cardiogenic shock, pericardial effusion (progressing to cardiac tamponade), myocardial hemorrhage, myocardial infarction, cardiac failure (including fatal outcomes), cardiomyopathy, myocarditis, pericarditis, carditis, atrial fibrillation, supraventricular arrhythmia, ventricular arrhythmia, bradycardia, tachycardia, palpitations, QT prolongation Congenital, familial and genetic: Intrauterine