systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.fluvoxamineSerious - Use Alternative (1)fluvoxamine and nefazodone both increase serotonin levels. Avoid or Use Alternate Drug.fosamprenavirSerious - Use Alternative (1)nefazodone will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.fosaprepitantSerious - Use Alternative (1)nefazodone will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.fosphenytoinMonitor Closely (1)fosphenytoin will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fostamatinibMonitor Closely (1)nefazodone will increase the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors may increase exposure to R406 (fostamatinib major active metabolite). Monitor for toxicities that may require fostamatinib dose reduction.frovatriptanMonitor Closely (1)frovatriptan and nefazodone both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)nefazodone, frovatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.furosemideMinor (1)furosemide, nefazodone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.gabapentinMonitor Closely (1)gabapentin, nefazodone. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.gabapentin enacarbilMonitor Closely (1)gabapentin enacarbil, nefazodone. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.galantamineMonitor Closely (1)nefazodone will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ganaxoloneMonitor Closely (1)nefazodone and ganaxolone both increase sedation. Use Caution/Monitor.Minor (1)nefazodone, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.gefitinibMonitor Closely (1)nefazodone increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.gentamicinMonitor Closely (1)nefazodone will increase the level or effect of gentamicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.gilteritinibSerious - Use Alternative (1)nefazodone will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.glasdegibSerious - Use Alternative (1)nefazodone will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternate therapies that are not strong CYP3A inhibitors or monitor for increased risk of adverse effects, including QTc interval prolongation.glecaprevir/pibrentasvirMonitor Closely (1)nefazodone will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.guanfacineMonitor Closely (1)nefazodone will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available. haloperidolMonitor Closely (1)nefazodone will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.hydrocodoneMonitor Closely (2)hydrocodone, nefazodone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. nefazodone will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depressionhydrocortisoneMonitor Closely (1)nefazodone will increase the level or effect of hydrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.hydroxyprogesterone caproate (DSC)Minor (1)nefazodone will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ibrutinibSerious - Use Alternative (1)nefazodone increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.ibuprofenMonitor Closely (1)nefazodone, ibuprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.ibuprofen IVMonitor Closely (1)nefazodone, ibuprofen IV. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.idelalisibSerious - Use Alternative (2)nefazodone will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur idelalisib will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substratesifosfamideMonitor Closely (1)nefazodone will decrease the level or effect of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of CYP3A4 inhibitors may decrease the metabolism of ifosfamide to its active alkylating metabolites and decrease the efficacy of ifosfamide.iloperidoneMonitor Closely (1)iloperidone increases levels of nefazodone 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.Serious - Use Alternative (1)nefazodone will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.imatinibMonitor Closely (2)nefazodone will increase the level or effect of imatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. nefazodone will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.imipramineMonitor Closely (1)nefazodone will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone and imipramine both increase serotonin levels. Avoid or Use Alternate Drug.indinavirMonitor Closely (2)nefazodone will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. nefazodone will increase the level or effect of indinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)indinavir will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.indomethacinMonitor Closely (1)nefazodone, indomethacin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.infigratinibSerious - Use Alternative (1)nefazodone will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.iobenguane I 123Contraindicated (1)nefazodone decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.irinotecanSerious - Use Alternative (2)nefazodone will increase the level or effect of irinotecan by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. nefazodone will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.irinotecan liposomalSerious - Use Alternative (2)nefazodone will increase the level or effect of irinotecan liposomal by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. nefazodone will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.isavuconazonium sulfateContraindicated (1)nefazodone will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.isocarboxazidContraindicated (1)isocarboxazid and nefazodone both increase serotonin levels. Contraindicated.isoniazidMonitor Closely (1)nefazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.isradipineSerious - Use Alternative (1)nefazodone will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.istradefyllineMonitor Closely (2)istradefylline will increase the level or effect of nefazodone 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. nefazodone will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed istradefylline 20 mg/day if coadministered with strong CYP3A4 inhibitors.itraconazoleMonitor Closely (2)nefazodone will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. nefazodone will increase the level or effect of itraconazole by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)itraconazole will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.ivabradineContraindicated (1)nefazodone will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.ivacaftorMonitor Closely (1)nefazodone will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with strong CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.ivermectinMonitor Closely (1)nefazodone will increase the level or effect of ivermectin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ivosidenibSerious - Use Alternative (2)nefazodone will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with ivosidenib or replace with alternate therapies. If coadministration of a strong CYP3A4 inhibitor is unavoidable, reduce ivosidenib dose to 250 mg qDay. If the strong inhibitor is discontinued, increase ivosidenib dose (after at least 5 half-lives of the strong CYP3A4 inhibitor) to the recommended dose of 500 mg qDay. Monitor for increased risk of QTc interval prolongation. ivosidenib will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.ixabepiloneSerious - Use Alternative (1)nefazodone will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.ixazomibMinor (1)nefazodone, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.ketamineSerious - Use Alternative (1)nefazodone will increase the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.ketoconazoleMonitor Closely (2)nefazodone will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. ketoconazole will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ketoprofenMonitor Closely (1)nefazodone, ketoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.ketorolacMonitor Closely (1)nefazodone, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.ketorolac intranasalMonitor Closely (1)nefazodone, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.L-tryptophanMonitor Closely (1)nefazodone and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.lacosamideMonitor Closely (1)nefazodone increases levels of lacosamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.lansoprazoleMonitor Closely (1)nefazodone will increase the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lapatinibMonitor Closely (1)nefazodone will increase the level or effect of lapatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.larotrectinibSerious - Use Alternative (1)nefazodone will increase the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of larotrectinib with strong CYP3A4 inhibitors is unavoidable, reduce larotrectinib dose by 50%. Resume prior larotrectinib dose once CYP3A4 inhibitor discontinued for 3-5 half-lives.lasmiditanMonitor Closely (1)lasmiditan, nefazodone. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.lefamulinSerious - Use Alternative (1)nefazodone will increase the level or effect of lefamulin by