(eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).dexchlorpheniraminedexchlorpheniramine and fluphenazine both increase sedation. Use Caution/Monitor.dexfenfluraminefluphenazine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, dexfenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.dexmedetomidinedexmedetomidine and fluphenazine both increase sedation. Use Caution/Monitor.dexmethylphenidatefluphenazine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, dexmethylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.dextroamphetaminefluphenazine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, dextroamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.dextromethorphandextromethorphan, fluphenazine. 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).dextromoramidedextromoramide and fluphenazine both increase sedation. Use Caution/Monitor.diamorphinediamorphine and fluphenazine both increase sedation. Use Caution/Monitor.diazepamdiazepam and fluphenazine both increase sedation. Use Caution/Monitor.dicyclominedicyclomine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.dicyclomine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diethylpropionfluphenazine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, diethylpropion. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.difelikefalindifelikefalin and fluphenazine both increase sedation. Use Caution/Monitor.difenoxin hcldifenoxin hcl and fluphenazine both increase sedation. Use Caution/Monitor.dihydroergotaminedihydroergotamine, fluphenazine. 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).dimenhydrinatedimenhydrinate and fluphenazine both increase sedation. Use Caution/Monitor.diphenhydraminediphenhydramine and fluphenazine both increase sedation. Use Caution/Monitor.diphenhydramine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.diphenhydramine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diphenoxylate hcldiphenoxylate hcl and fluphenazine both increase sedation. Use Caution/Monitor.dipipanonedipipanone and fluphenazine both increase sedation. Use Caution/Monitor.dobutaminefluphenazine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, dobutamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.dofetilidedofetilide increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.dolasetronfluphenazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.donepezildonepezil and fluphenazine both increase QTc interval. Use Caution/Monitor.donepezil transdermaldonepezil transdermal, fluphenazine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dopaminefluphenazine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, dopamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.dopexaminefluphenazine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dosulepinfluphenazine and dosulepin both increase sedation. Use Caution/Monitor.doxepinfluphenazine and doxepin both increase sedation. Use Caution/Monitor.doxylaminedoxylamine and fluphenazine both increase sedation. Use Caution/Monitor.droperidoldroperidol and fluphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.droperidol and fluphenazine both increase sedation. Use Caution/Monitor.efavirenzefavirenz and fluphenazine both increase QTc interval. Use Caution/Monitor.eletriptaneletriptan, fluphenazine. 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).eliglustateliglustat increases levels of fluphenazine 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.eliglustat and fluphenazine both increase QTc interval. Use Caution/Monitor.elvitegravir/cobicistat/emtricitabine/tenofovir DFelvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fluphenazine 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.encorafenibencorafenib and fluphenazine both increase QTc interval. Use Caution/Monitor.entrectinibentrectinib and fluphenazine both increase QTc interval. Use Caution/Monitor.ephedrinefluphenazine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, ephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.epinephrinefluphenazine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, epinephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.fluphenazine decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.epinephrine racemicfluphenazine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.ergoloid mesylatesergoloid mesylates, fluphenazine. 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).ergotamineergotamine, fluphenazine. 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).eribulineribulin and fluphenazine both increase QTc interval. Use Caution/Monitor.escitalopramescitalopram increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.esketamine intranasalesketamine intranasal, fluphenazine. Either increases toxicity of the other by sedation. Use Caution/Monitor.estazolamestazolam and fluphenazine both increase sedation. Use Caution/Monitor.ethanolfluphenazine and ethanol both increase sedation. Use Caution/Monitor.etomidateetomidate and fluphenazine both increase sedation. Use Caution/Monitor.fedratinibfedratinib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.fenfluraminefluphenazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluphenazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.fentanylfentanyl, fluphenazine. 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).fesoterodinefesoterodine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.fesoterodine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.fingolimodfingolimod and fluphenazine both increase QTc interval. Use Caution/Monitor.flavoxateflavoxate decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.flavoxate decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flecainidefluphenazine and flecainide both increase QTc interval. Modify Therapy/Monitor Closely.flibanserinflibanserin, fluphenazine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. 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).flurazepamflurazepam and fluphenazine both increase sedation. Use Caution/Monitor.fluvoxaminefluvoxamine and fluphenazine both increase QTc interval. Use Caution/Monitor.formoterolfluphenazine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.foscarnetfluphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.fostemsavirfluphenazine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir. frovatriptanfrovatriptan, fluphenazine. 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).ganaxolonefluphenazine and ganaxolone both increase sedation. Use Caution/Monitor.gemifloxacingemifloxacin and fluphenazine both increase QTc interval. Use Caution/Monitor.gilteritinibgilteritinib and fluphenazine both increase QTc interval. Use Caution/Monitor.glycopyrrolatefluphenazine increases toxicity of glycopyrrolate by unknown mechanism. Use Caution/Monitor.fluphenazine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrrolate inhaledglycopyrrolate inhaled decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.glycopyrrolate inhaled decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.fluphenazine increases toxicity of glycopyrrolate inhaled by unknown mechanism. Use Caution/Monitor.glycopyrronium tosylate topicalglycopyrronium tosylate topical, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.granisetrongranisetron and fluphenazine both increase QTc interval. Use Caution/Monitor.guanfacineguanfacine, fluphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.haloperidolfluphenazine and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.fluphenazine and haloperidol both increase sedation. Use Caution/Monitor.henbanehenbane decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.henbane decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.homatropinehomatropine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.homatropine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hydromorphonehydromorphone and fluphenazine both increase sedation. Use Caution/Monitor.hydroxyzinehydroxyzine and fluphenazine both increase sedation. Use Caution/Monitor.hydroxyzine and fluphenazine both increase QTc interval. Use Caution/Monitor.hyoscyaminehyoscyamine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.fluphenazine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayfluphenazine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine spray decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine spray decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.iloperidonefluphenazine and iloperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.fluphenazine and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.fluphenazine and iloperidone both increase sedation. Use Caution/Monitor.imipraminefluphenazine and imipramine both increase sedation. Use Caution/Monitor.incobotulinumtoxinAfluphenazine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.indacaterol, inhaledindacaterol, inhaled, fluphenazine. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.insulin degludecfluphenazine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.insulin degludec/insulin aspartfluphenazine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.insulin inhaledfluphenazine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.ipratropiumipratropium decreases levels of fluphenazine by