of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.tipranavirtipranavir will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.trazodonefesoterodine and trazodone both decrease cholinergic effects/transmission. Minor/Significance Unknown.venlafaxinevenlafaxine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.abobotulinumtoxinAMonitor Closely (1)abobotulinumtoxinA increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects. .aclidiniumMonitor Closely (1)fesoterodine and aclidinium both decrease cholinergic effects/transmission. Use Caution/Monitor.amantadineMonitor Closely (1)fesoterodine, amantadine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Potential for increased anticholinergic adverse effects.amiodaroneMinor (1)amiodarone will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.amitriptylineMonitor Closely (1)fesoterodine and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.amobarbitalMonitor Closely (1)amobarbital will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.amoxapineMonitor Closely (1)fesoterodine and amoxapine both decrease cholinergic effects/transmission. Use Caution/Monitor.anticholinergic/sedative combosMonitor Closely (1)anticholinergic/sedative combos and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.aprepitantMonitor Closely (1)aprepitant will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.aripiprazoleMonitor Closely (3)fesoterodine decreases levels of aripiprazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of aripiprazole by pharmacodynamic antagonism. Use Caution/Monitor. aripiprazole increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.armodafinilMonitor Closely (1)armodafinil will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.artemether/lumefantrineMonitor Closely (2)artemether/lumefantrine will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. artemether/lumefantrine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.asenapineMinor (1)asenapine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.atazanavirMonitor Closely (1)atazanavir will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.atracuriumMonitor Closely (1)atracurium and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.atropineMonitor Closely (1)atropine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.atropine IV/IMMonitor Closely (1)atropine IV/IM and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.belladonna alkaloidsMonitor Closely (1)belladonna alkaloids and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.belladonna and opiumMonitor Closely (1)fesoterodine and belladonna and opium both decrease cholinergic effects/transmission. Use Caution/Monitor.benperidolMonitor Closely (3)fesoterodine decreases levels of benperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of benperidol by pharmacodynamic antagonism. Use Caution/Monitor. benperidol increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.benztropineMonitor Closely (1)benztropine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. bethanecholMonitor Closely (1)bethanechol increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.bosentanMonitor Closely (1)bosentan will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.budesonideMonitor Closely (1)budesonide will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.bupropionMonitor Closely (1)bupropion will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.butabarbitalMonitor Closely (1)butabarbital will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.butalbitalMonitor Closely (1)butalbital will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.carbacholMonitor Closely (1)carbachol increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.carbamazepineSerious - Use Alternative (1)carbamazepine will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.celecoxibMinor (1)celecoxib will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cevimelineMonitor Closely (1)cevimeline increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.chloroquineMinor (1)chloroquine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.chlorpromazineMonitor Closely (3)fesoterodine decreases levels of chlorpromazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of chlorpromazine by pharmacodynamic antagonism. Use Caution/Monitor. chlorpromazine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.cimetidineSerious - Use Alternative (1)cimetidine will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)cimetidine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cisatracuriumMonitor Closely (1)cisatracurium and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.clarithromycinSerious - Use Alternative (1)clarithromycin will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.clomipramineMonitor Closely (1)fesoterodine and clomipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.clozapineMonitor Closely (3)fesoterodine decreases levels of clozapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of clozapine by pharmacodynamic antagonism. Use Caution/Monitor. clozapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.conivaptanMonitor Closely (1)conivaptan will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.cortisoneMonitor Closely (1)cortisone will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.crizotinibMonitor Closely (1)crizotinib increases levels of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.cyclizineMonitor Closely (1)cyclizine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.cyclobenzaprineMonitor Closely (1)cyclobenzaprine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.cyclosporineMonitor Closely (1)cyclosporine will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.darifenacinMonitor Closely (2)darifenacin will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. darifenacin and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.Minor (1)darifenacin will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.darunavirMonitor Closely (1)darunavir will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dasatinibMonitor Closely (1)dasatinib will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.deferasiroxMonitor Closely (1)deferasirox will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.desipramineMinor (1)fesoterodine and desipramine both decrease cholinergic effects/transmission. Minor/Significance Unknown.desvenlafaxineMonitor Closely (1)desvenlafaxine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mgdexamethasoneMonitor Closely (1)dexamethasone will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.DHEA, herbalMonitor Closely (1)DHEA, herbal will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dicyclomineMonitor Closely (1)dicyclomine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.diltiazemMonitor Closely (1)diltiazem will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dimenhydrinateMinor (1)dimenhydrinate increases toxicity of fesoterodine by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.diphenhydramineMonitor Closely (1)diphenhydramine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.Minor (1)diphenhydramine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.donepezilMonitor Closely (1)donepezil increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)donepezil decreases effects of fesoterodine by pharmacodynamic antagonism. Minor/Significance Unknown.donepezil transdermalMonitor Closely (1)donepezil transdermal, fesoterodine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dosulepinMonitor Closely (1)fesoterodine and dosulepin both decrease cholinergic effects/transmission. Use Caution/Monitor.doxepinMonitor Closely (1)fesoterodine and doxepin both decrease cholinergic effects/transmission. Use Caution/Monitor.dronedaroneMonitor Closely (1)dronedarone will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)dronedarone will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.droperidolMonitor Closely (3)fesoterodine decreases levels of droperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of droperidol by pharmacodynamic antagonism. Use Caution/Monitor. droperidol increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.duloxetineMonitor Closely (1)duloxetine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.echothiophate iodideMonitor Closely (1)echothiophate iodide increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.efavirenzMonitor Closely (1)efavirenz will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin baseSerious - Use Alternative (1)erythromycin base will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin ethylsuccinateSerious - Use Alternative (1)erythromycin ethylsuccinate will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin lactobionateSerious - Use Alternative (1)erythromycin lactobionate will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin stearateSerious - Use Alternative (1)erythromycin stearate will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eslicarbazepine acetateMinor (1)eslicarbazepine acetate will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etravirineMonitor Closely (1)etravirine will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.flavoxateMonitor Closely (1)fesoterodine and flavoxate both decrease cholinergic effects/transmission. Use Caution/Monitor.fluconazoleMonitor Closely (1)fluconazole will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fludrocortisoneMonitor Closely (1)fludrocortisone will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluoxetineMonitor Closely (1)fluoxetine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.fluphenazineMonitor Closely (3)fesoterodine 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.fluvoxamineMonitor Closely (1)fluvoxamine will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosamprenavirMonitor Closely (1)fosamprenavir will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosaprepitantMonitor Closely (1)fosaprepitant will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosphenytoinMonitor Closely (1)fosphenytoin will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.galantamineMonitor Closely (1)galantamine increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)galantamine decreases effects of fesoterodine by pharmacodynamic antagonism. Minor/Significance Unknown.givosiranSerious - Use Alternative (1)givosiran will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.glycopyrrolateMonitor Closely (1)fesoterodine and glycopyrrolate both decrease cholinergic effects/transmission. Use Caution/Monitor.glycopyrrolate inhaledMonitor Closely (1)fesoterodine and glycopyrrolate inhaled both decrease cholinergic effects/transmission. Use Caution/Monitor.glycopyrronium tosylate topicalSerious - Use Alternative (1)glycopyrronium tosylate topical, fesoterodine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.grapefruitMonitor Closely (1)grapefruit will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.griseofulvinMonitor Closely (1)griseofulvin will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.haloperidolMonitor Closely (3)fesoterodine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor. haloperidol increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)haloperidol will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.henbaneMonitor Closely (1)fesoterodine and henbane both decrease cholinergic effects/transmission. Use Caution/Monitor.homatropineMonitor Closely (1)fesoterodine and homatropine both decrease cholinergic effects/transmission. Use Caution/Monitor.huperzine AMonitor Closely (1)huperzine A increases and fesoterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydrocortisoneMonitor Closely (1)hydrocortisone will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.hyoscyamineMonitor Closely (1)fesoterodine and hyoscyamine both decrease cholinergic effects/transmission. Use Caution/Monitor.hyoscyamine sprayMonitor Closely (1)fesoterodine and hyoscyamine spray both decrease cholinergic effects/transmission. Use Caution/Monitor.iloperidoneMonitor Closely (3)fesoterodine decreases levels of iloperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of iloperidone by pharmacodynamic antagonism. Use Caution/Monitor. iloperidone increases