venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)venlafaxine and lofepramine both increase serotonin levels. Avoid or Use Alternate Drug.lonafarnibSerious - Use Alternative (1)lonafarnib will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.lopinavirMonitor Closely (1)lopinavir increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity.loratadineMonitor Closely (1)venlafaxine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lorcaserinMonitor Closely (1)lorcaserin will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)venlafaxine and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.lornoxicamMonitor Closely (1)venlafaxine, lornoxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.loxapineMonitor Closely (1)venlafaxine, loxapine. 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).loxapine inhaledMonitor Closely (1)venlafaxine, loxapine inhaled. 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).lsdMonitor Closely (1)venlafaxine and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.lumefantrineMonitor Closely (1)lumefantrine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.lurasidoneMonitor Closely (2)lurasidone, venlafaxine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity. venlafaxine, lurasidone. 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).maprotilineMonitor Closely (1)maprotiline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)venlafaxine and maprotiline both increase serotonin levels. Avoid or Use Alternate Drug.meclofenamateMonitor Closely (1)venlafaxine, meclofenamate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.mefenamic acidMonitor Closely (1)venlafaxine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.mefloquineSerious - Use Alternative (1)mefloquine increases toxicity of venlafaxine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.meloxicamMonitor Closely (1)venlafaxine, meloxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.meperidineSerious - Use Alternative (1)venlafaxine and meperidine both increase serotonin levels. Avoid or Use Alternate Drug.methadoneMonitor Closely (1)methadone and venlafaxine both increase QTc interval. Use Caution/Monitor.methamphetamineMonitor Closely (1)venlafaxine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.methylene blueSerious - Use Alternative (1)methylene blue and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug. Methylene blue may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last methylene blue dose or after 2 weeks of monitoring, whichever comes first.metoclopramideSerious - Use Alternative (1)metoclopramide and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug. Additive effects; increased risk for serotonin syndrome, neuroleptic malignant syndrome, dystonia, or other extrapyramidal reactionsmetoprololMonitor Closely (1)venlafaxine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mexiletineMonitor Closely (1)venlafaxine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mifepristoneMonitor Closely (1)mifepristone will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.milnacipranSerious - Use Alternative (1)milnacipran and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.mirabegronMonitor Closely (1)mirabegron will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineMonitor Closely (1)venlafaxine and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)mirtazapine and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.mitotaneMonitor Closely (1)mitotane will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor and adjust venlafaxine dose as necessarymolindoneMonitor Closely (1)venlafaxine, molindone. 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).morphineMonitor Closely (2)venlafaxine and morphine both increase serotonin levels. Modify Therapy/Monitor Closely. venlafaxine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.moxifloxacinMonitor Closely (1)moxifloxacin and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.nabumetoneMonitor Closely (1)venlafaxine, nabumetone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.nalbuphineSerious - Use Alternative (1)venlafaxine and nalbuphine both increase serotonin levels. Avoid or Use Alternate Drug. May cause serotonin syndromenaproxenMonitor Closely (1)venlafaxine, naproxen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.naratriptanMonitor Closely (1)naratriptan and venlafaxine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)venlafaxine, naratriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.nebivololMonitor Closely (1)venlafaxine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.nefazodoneSerious - Use Alternative (2)nefazodone and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug. nefazodone will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.netupitant/palonosetronSerious - Use Alternative (1)netupitant/palonosetron, venlafaxine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.nilotinibMonitor Closely (1)nilotinib and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.nirmatrelvir/ritonavirMonitor Closely (1)nirmatrelvir/ritonavir increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .nortriptylineMonitor Closely (1)nortriptyline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)venlafaxine and nortriptyline both increase serotonin levels. Avoid or Use Alternate Drug. venlafaxine will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.octreotideMonitor Closely (1)octreotide and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.octreotide (Antidote)Monitor Closely (1)octreotide (Antidote) and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.ofloxacinMonitor Closely (1)ofloxacin and venlafaxine both increase QTc interval. Use Caution/Monitor.olanzapineMonitor Closely (2)venlafaxine, olanzapine. 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). olanzapine and venlafaxine both decrease QTc interval. Use Caution/Monitor.oliceridineMonitor Closely (1)venlafaxine, oliceridine. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely.ondansetronSerious - Use Alternative (1)ondansetron, venlafaxine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.opium tinctureSerious - Use Alternative (1)venlafaxine and opium tincture both increase serotonin levels. Avoid or Use Alternate Drug. May cause serotonin syndromeoxaliplatinSerious - Use Alternative (1)oxaliplatin and venlafaxine both decrease QTc interval. Avoid or Use Alternate Drug.oxaprozinMonitor Closely (1)venlafaxine, oxaprozin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.oxycodoneMonitor Closely (1)venlafaxine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Minor (1)venlafaxine decreases effects of oxycodone by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of oxycodone to active metabolite morphine.oxymorphoneMonitor Closely (1)venlafaxine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.ozanimodSerious - Use Alternative (1)ozanimod increases toxicity of venlafaxine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.paliperidoneMonitor Closely (2)venlafaxine, paliperidone. 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). paliperidone and venlafaxine both increase QTc interval. Use Caution/Monitor.palonosetronSerious - Use Alternative (1)palonosetron, venlafaxine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.panax ginsengMinor (1)panax ginseng increases effects of venlafaxine by pharmacodynamic synergism. Minor/Significance Unknown.panobinostatMonitor Closely (1)panobinostat will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Panobinostat can increase the levels and effects of sensitive CYP2D6 substrates or those with a narrow therapeutic index CYP2D6.parecoxibMonitor Closely (1)venlafaxine, parecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.paroxetineMonitor Closely (1)paroxetine and venlafaxine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)paroxetine and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.Minor (1)venlafaxine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.pazopanibMinor (1)pazopanib and venlafaxine both increase QTc interval. Minor/Significance Unknown.peginterferon alfa 2bMonitor Closely (1)peginterferon alfa 2b, venlafaxine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.pentamidineSerious - Use Alternative (1)pentamidine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.pentazocineMonitor Closely (1)venlafaxine and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.perhexilineMinor (1)venlafaxine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.perphenazineMonitor Closely (2)venlafaxine, perphenazine. 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). venlafaxine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.phenelzineContraindicated (1)phenelzine and venlafaxine both increase serotonin levels. Contraindicated.phentermineSerious - Use Alternative (1)venlafaxine, phentermine. Either increases toxicity of the other by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of serotonin syndrome.pimavanserinMonitor Closely (1)venlafaxine, pimavanserin. 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).pimozideMonitor Closely (1)venlafaxine, pimozide. 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).Serious - Use Alternative (1)pimozide and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.piroxicamMonitor Closely (1)venlafaxine, piroxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor.