of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.L-tryptophanvenlafaxine and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.lapatiniblapatinib and venlafaxine both increase QTc interval. Use Caution/Monitor.lasmiditanlasmiditan, venlafaxine. 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.venlafaxine increases effects of lasmiditan by serotonin levels. Use Caution/Monitor. Coadministration may increase risk of serotonin syndrome.lemborexantlemborexant, venlafaxine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.lenacapavirlenacapavir will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.levofloxacinlevofloxacin and venlafaxine both increase QTc interval. Use Caution/Monitor.levoketoconazolelevoketoconazole will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.levoketoconazole and venlafaxine both increase QTc interval. Use Caution/Monitor.lisdexamfetaminevenlafaxine, lisdexamfetamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue along with concomitant serotonergic drug(s).lithiumvenlafaxine and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.lithium and venlafaxine both decrease QTc interval. Use Caution/Monitor.lofepraminevenlafaxine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lofepramine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.lopinavirlopinavir increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity.loratadinevenlafaxine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lorcaserinlorcaserin will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lornoxicamvenlafaxine, 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.loxapinevenlafaxine, 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 inhaledvenlafaxine, 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).lsdvenlafaxine and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.lumefantrinelumefantrine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.lurasidonelurasidone, 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).maprotilinemaprotiline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.meclofenamatevenlafaxine, 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 acidvenlafaxine, 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.meloxicamvenlafaxine, 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.methadonemethadone and venlafaxine both increase QTc interval. Use Caution/Monitor.methamphetaminevenlafaxine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.metoprololvenlafaxine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mexiletinevenlafaxine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mifepristonemifepristone will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.mirabegronmirabegron will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapinevenlafaxine and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.mitotanemitotane will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor and adjust venlafaxine dose as necessarymolindonevenlafaxine, 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).morphinevenlafaxine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.venlafaxine and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.moxifloxacinmoxifloxacin and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.nabumetonevenlafaxine, 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.naproxenvenlafaxine, 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.naratriptannaratriptan and venlafaxine both increase serotonin levels. Modify Therapy/Monitor Closely.nebivololvenlafaxine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.nilotinibnilotinib and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.nirmatrelvir/ritonavirnirmatrelvir/ritonavir increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .nortriptylinenortriptyline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.octreotideoctreotide and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.octreotide (Antidote)octreotide (Antidote) and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.ofloxacinofloxacin and venlafaxine both increase QTc interval. Use Caution/Monitor.olanzapinevenlafaxine, 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.oliceridinevenlafaxine, oliceridine. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely.oxaprozinvenlafaxine, 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.oxycodonevenlafaxine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.oxymorphonevenlafaxine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.paliperidonepaliperidone and venlafaxine both increase QTc interval. Use Caution/Monitor.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).panobinostatpanobinostat 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.parecoxibvenlafaxine, 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.paroxetineparoxetine and venlafaxine both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bpeginterferon 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.pentazocinevenlafaxine and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.perphenazinevenlafaxine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.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).pimavanserinvenlafaxine, 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).pimozidevenlafaxine, 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).piroxicamvenlafaxine, piroxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.posaconazoleposaconazole and venlafaxine both increase QTc interval. Use Caution/Monitor.pregabalinpregabalin, venlafaxine. 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.primaquineprimaquine and venlafaxine both decrease QTc interval. Use Caution/Monitor.prochlorperazinevenlafaxine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.prochlorperazine and venlafaxine both increase QTc interval. Use Caution/Monitor.promazinepromazine and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.promethazinepromethazine and venlafaxine both increase QTc interval. Use Caution/Monitor.propafenonevenlafaxine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.propranololvenlafaxine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.protriptylineprotriptyline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.quetiapinevenlafaxine, quetiapine. 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).ranolazineranolazine and venlafaxine both increase QTc interval. Use Caution/Monitor.remimazolamremimazolam, venlafaxine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.risperidonevenlafaxine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.risperidone and venlafaxine both increase QTc interval. Use Caution/Monitor.venlafaxine, risperidone. 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).ritonavirritonavir increases levels of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .rizatriptanrizatriptan and venlafaxine both increase serotonin levels. Modify Therapy/Monitor Closely.rolapitantrolapitant will increase the level or effect of venlafaxine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.romidepsinromidepsin and venlafaxine both increase QTc interval. Use Caution/Monitor.rucaparibrucaparib will increase the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.salicylates (non-asa)venlafaxine, salicylates (non-asa). Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.salsalatevenlafaxine, salsalate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.SAMevenlafaxine and SAMe both increase serotonin levels. Modify Therapy/Monitor Closely.sodium sulfate/potassium chloride/magnesium sulfate/polyethylene glycolvenlafaxine, sodium sulfate/potassium chloride/magnesium sulfate/polyethylene glycol. Other (see comment). Use Caution/Monitor. Comment: Caution when bowel preps are used with drugs that cause SIADH or NSAIDs; increased risk for