contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors nefazodone increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.elvitegravirMonitor Closely (1)nefazodone increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.elvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (2)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events. nefazodone will increase the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of nefazodone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.encorafenibMonitor Closely (1)encorafenib, nefazodone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.Serious - Use Alternative (1)nefazodone will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-third of the dose (eg, reduce from 450 mg/day to 150 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.enfortumab vedotinMonitor Closely (1)nefazodone increases toxicity of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Enfortumab vedotin is an antibody-drug conjugate that releases monomethylauristatin E (MMAE) via proteolytic cleavage. MMAE is primarily metabolized by CYP3A4 in vitro. Coadministration with strong CYP3A4 inhibitors may increase free MMAE exposure, which may increase the incidence or severity of toxicities.entrectinibSerious - Use Alternative (1)nefazodone will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce entrectinib dose to 100 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing strong CYP3A inhibitor for 3-5 elimination half-lives.enzalutamideMonitor Closely (2)nefazodone will increase the level or effect of enzalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. enzalutamide will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.eplerenoneContraindicated (1)nefazodone will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.erdafitinibSerious - Use Alternative (1)nefazodone will increase the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP3A4 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.ergonovineContraindicated (1)nefazodone will increase the level or effect of ergonovine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.ergotamineMonitor Closely (1)nefazodone and ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)nefazodone will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erlotinibMonitor Closely (1)nefazodone will increase the level or effect of erlotinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin baseSerious - Use Alternative (1)nefazodone will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin ethylsuccinateSerious - Use Alternative (1)nefazodone will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin lactobionateSerious - Use Alternative (1)nefazodone will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin stearateSerious - Use Alternative (1)nefazodone will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.escitalopramSerious - Use Alternative (2)escitalopram and nefazodone both increase serotonin levels. Avoid or Use Alternate Drug. nefazodone will increase the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.estradiolMonitor Closely (1)nefazodone will increase the level or effect of estradiol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.estradiol vaginalMonitor Closely (1)nefazodone will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase plasma concentrations of estrogens and toxicities.estrogens conjugated syntheticMonitor Closely (1)nefazodone will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.estrogens esterifiedMonitor Closely (1)nefazodone will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.estropipateMonitor Closely (1)nefazodone will increase the level or effect of estropipate by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eszopicloneSerious - Use Alternative (1)nefazodone will increase the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.ethacrynic acidMinor (1)ethacrynic acid, nefazodone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.ethinylestradiolMinor (1)nefazodone will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ethosuximideSerious - Use Alternative (1)nefazodone will increase the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.etodolacMonitor Closely (1)nefazodone, etodolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.etonogestrelMinor (1)nefazodone will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etoposideMonitor Closely (1)nefazodone will increase the level or effect of etoposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.etravirineMonitor Closely (1)etravirine will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eucalyptusMinor (1)nefazodone will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.everolimusSerious - Use Alternative (2)nefazodone will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. nefazodone will increase the level or effect of everolimus by P-glycoprotein (MDR1) efflux transporter. Contraindicated.fedratinibMonitor Closely (1)fedratinib will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.Serious - Use Alternative (1)nefazodone will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid fedratinib coadministration with strong CYP3A4 inhibitors, decrease fedratinib dose to 200 mg/day. If CYP3A4 inhibitor discontinued, increase fedratinib dose to 300 mg/day for 2 weeks, and then 400 mg/day thereafter as tolerated.felbamateSerious - Use Alternative (1)nefazodone will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.felodipineSerious - Use Alternative (1)nefazodone will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.fenbufenMonitor Closely (1)nefazodone, fenbufen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.fenfluramineMonitor Closely (2)fenfluramine, nefazodone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. nefazodone and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.fenoprofenMonitor Closely (1)nefazodone, fenoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.fentanylSerious - Use Alternative (1)nefazodone will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl intranasalSerious - Use Alternative (1)nefazodone will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl transdermalSerious - Use Alternative (1)nefazodone will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl transmucosalSerious - Use Alternative (1)nefazodone will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fesoterodineMonitor Closely (1)nefazodone will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.fexinidazoleSerious - Use Alternative (2)nefazodone will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites. fexinidazole will increase the level or effect of nefazodone 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.fexofenadineMonitor Closely (1)nefazodone will increase the level or effect of fexofenadine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.fezolinetantContraindicated (1)nefazodone will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitorsfinasterideMonitor Closely (1)nefazodone will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.finerenoneContraindicated (1)nefazodone will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.flibanserinContraindicated (1)nefazodone will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.fludrocortisoneMonitor Closely (1)nefazodone will increase the level or effect of fludrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.flunisolide inhaledMonitor Closely (1)nefazodone will increase the level or effect of flunisolide inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluoxetineSerious - Use Alternative (1)fluoxetine and nefazodone both increase serotonin levels. Avoid or Use Alternate Drug.flurazepamMonitor Closely (1)nefazodone will increase the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.flurbiprofenMonitor Closely (1)nefazodone, flurbiprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.fluticasone furoateMonitor Closely (1)nefazodone will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposurefluticasone inhaledMonitor Closely (1)nefazodone will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposurefluticasone intranasalSerious - Use Alternative (1)nefazodone will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase