carefully observe the patient, particularly during treatment initiation and dose adjustment.bumetanideMinor (1)bumetanide, venlafaxine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.buprenorphineSerious - Use Alternative (1)buprenorphine and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.buprenorphine buccalSerious - Use Alternative (1)buprenorphine buccal and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.buprenorphine subdermal implantMonitor Closely (1)venlafaxine, buprenorphine subdermal implant. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.Serious - Use Alternative (1)buprenorphine subdermal implant and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.buprenorphine transdermalSerious - Use Alternative (1)buprenorphine transdermal and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.buprenorphine, long-acting injectionMonitor Closely (1)venlafaxine, buprenorphine, long-acting injection. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.Serious - Use Alternative (1)buprenorphine, long-acting injection and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.bupropionMonitor Closely (1)bupropion will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)venlafaxine increases toxicity of bupropion by unspecified interaction mechanism. Avoid or Use Alternate Drug. May lower seizure threshold; keep bupropion dose as low as possible.buspironeSerious - Use Alternative (1)venlafaxine and buspirone both increase serotonin levels. Avoid or Use Alternate Drug.cariprazineMonitor Closely (1)venlafaxine, cariprazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).carvedilolMonitor Closely (1)venlafaxine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.celandineMinor (1)celandine decreases effects of venlafaxine by pharmacodynamic antagonism. Minor/Significance Unknown. Based on animal studies.celecoxibMonitor Closely (1)venlafaxine, celecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.ceritinibSerious - Use Alternative (1)ceritinib will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.chloramphenicolMonitor Closely (1)chloramphenicol will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.chlorpromazineMonitor Closely (2)chlorpromazine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely. venlafaxine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.choline magnesium trisalicylateMonitor Closely (1)venlafaxine, choline magnesium trisalicylate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.citalopramSerious - Use Alternative (1)citalopram and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions.clarithromycinMonitor Closely (1)clarithromycin and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)clarithromycin will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.clobazamMonitor Closely (1)clobazam will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly. clomipramineMonitor Closely (2)venlafaxine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. clomipramine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)venlafaxine and clomipramine both increase serotonin levels. Avoid or Use Alternate Drug.clopidogrelMonitor Closely (1)venlafaxine increases effects of clopidogrel by pharmacodynamic synergism. Use Caution/Monitor. SNRIs affect platelet activation; coadministration of SNRIs with clopidogrel may increase the risk of bleeding.clozapineMonitor Closely (1)venlafaxine, clozapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).cobicistatMonitor Closely (1)cobicistat will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.cocaine topicalMonitor Closely (1)venlafaxine and cocaine topical both increase serotonin levels. Modify Therapy/Monitor Closely.codeineMonitor Closely (1)venlafaxine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Minor (1)venlafaxine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.crofelemerMonitor Closely (1)crofelemer increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.cyclobenzaprineSerious - Use Alternative (1)venlafaxine and cyclobenzaprine both increase serotonin levels. Avoid or Use Alternate Drug.cyclophosphamideMinor (1)cyclophosphamide will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cyproheptadineMonitor Closely (1)cyproheptadine decreases effects of venlafaxine by pharmacodynamic antagonism. Use Caution/Monitor. Cyproheptadine may diminish the serotonergic effect of SNRIs.dabrafenibMonitor Closely (1)dabrafenib will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.dacomitinibSerious - Use Alternative (1)dacomitinib will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities. dasatinibMonitor Closely (1)dasatinib and venlafaxine both increase QTc interval. Use Caution/Monitor.degarelixMonitor Closely (1)degarelix and venlafaxine both decrease QTc interval. Use Caution/Monitor.desfluraneSerious - Use Alternative (1)desflurane and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.desipramineMonitor Closely (2)venlafaxine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. desipramine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)venlafaxine and desipramine both increase serotonin levels. Avoid or Use Alternate Drug.deutetrabenazineMonitor Closely (1)deutetrabenazine and venlafaxine both decrease QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).dexfenfluramineMonitor Closely (1)venlafaxine and dexfenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)venlafaxine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.dexmethylphenidateMinor (1)dexmethylphenidate increases effects of venlafaxine by decreasing metabolism. Minor/Significance Unknown.dextroamphetamineMonitor Closely (2)venlafaxine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. venlafaxine and dextroamphetamine both increase serotonin levels. Modify Therapy/Monitor Closely.dextroamphetamine transdermalMonitor Closely (1)venlafaxine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s).dextromethorphanSerious - Use Alternative (2)venlafaxine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug. venlafaxine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.diazepam intranasalMonitor Closely (1)diazepam intranasal, venlafaxine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.dichlorphenamideMonitor Closely (1)dichlorphenamide and venlafaxine both decrease serum potassium. Use Caution/Monitor.diclofenacMonitor Closely (1)venlafaxine, diclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.diflunisalMonitor Closely (1)venlafaxine, diflunisal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.dihydroergotamineMonitor Closely (1)venlafaxine and dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.dihydroergotamine intranasalMonitor Closely (1)venlafaxine and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.disopyramideSerious - Use Alternative (1)disopyramide and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.dofetilideMonitor Closely (1)dofetilide and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.dolasetronMonitor Closely (1)dolasetron and venlafaxine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)dolasetron, venlafaxine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.donepezilMonitor Closely (1)donepezil and venlafaxine both decrease QTc interval. Use Caution/Monitor.Minor (1)venlafaxine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.dosulepinSerious - Use Alternative (1)venlafaxine and dosulepin both increase serotonin levels. Avoid or Use Alternate Drug.doxepinMonitor Closely (1)doxepin and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)venlafaxine and doxepin both increase serotonin levels. Avoid or Use Alternate Drug. venlafaxine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.dronedaroneMonitor Closely (1)dronedarone and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.droperidolMonitor Closely (1)droperidol and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.duloxetineMonitor Closely (1)venlafaxine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)duloxetine and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.efavirenzMonitor Closely (2)efavirenz will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. efavirenz and venlafaxine both decrease QTc interval. Use Caution/Monitor.elagolixMonitor Closely (1)elagolix decreases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.eletriptanMonitor Closely (1)eletriptan and venlafaxine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)venlafaxine, eletriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.eliglustatMonitor Closely (1)eliglustat increases levels of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.Serious - Use Alternative (1)eliglustat and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.elvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (2)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of venlafaxine 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. elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.encainideMinor (1)venlafaxine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.encorafenibMonitor Closely (1)encorafenib, venlafaxine. 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)encorafenib and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.entrectinibSerious - Use Alternative (1)entrectinib and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.epinephrineMonitor Closely (1)epinephrine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.epinephrine racemicMonitor Closely (1)epinephrine racemic and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.ergotamineMonitor Closely (1)venlafaxine and ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.eribulinSerious - Use Alternative (1)eribulin and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.erythromycin baseMonitor Closely (1)erythromycin base and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.erythromycin ethylsuccinateMonitor Closely (1)erythromycin ethylsuccinate and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.erythromycin lactobionateMonitor Closely (1)erythromycin lactobionate and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.erythromycin stearateMonitor Closely (1)erythromycin stearate and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.escitalopramSerious - Use Alternative (1)escitalopram and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.ethacrynic acidMinor (1)ethacrynic acid, venlafaxine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.etodolacMonitor Closely (1)venlafaxine, 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.fedratinibMonitor Closely (2)fedratinib will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary. fedratinib will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.fenbufenMonitor Closely (1)venlafaxine, fenbufen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor.