effects/transmission. Use Caution/Monitor.amantadineMonitor Closely (1)oxybutynin, amantadine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Potential for increased anticholinergic adverse effects.Minor (1)amantadine increases effects of oxybutynin by pharmacodynamic synergism. Minor/Significance Unknown.amitriptylineMonitor Closely (1)oxybutynin and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.amobarbitalMinor (1)amobarbital will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amoxapineMonitor Closely (1)oxybutynin and amoxapine both decrease cholinergic effects/transmission. Use Caution/Monitor.anticholinergic/sedative combosMonitor Closely (1)anticholinergic/sedative combos and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.aprepitantMinor (1)aprepitant will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aripiprazoleMonitor Closely (3)oxybutynin decreases levels of aripiprazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of aripiprazole by pharmacodynamic antagonism. Use Caution/Monitor. aripiprazole increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.armodafinilMinor (1)armodafinil will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.artemether/lumefantrineMinor (1)artemether/lumefantrine will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atazanavirMinor (1)atazanavir will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atenololMinor (1)atenolol increases levels of oxybutynin by decreasing metabolism. Minor/Significance Unknown.atracuriumMonitor Closely (1)atracurium and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.atropineMonitor Closely (1)atropine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.atropine IV/IMMonitor Closely (1)atropine IV/IM and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.avapritinibMonitor Closely (1)oxybutynin will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.axitinibMonitor Closely (1)oxybutynin increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.belladonna alkaloidsMonitor Closely (1)belladonna alkaloids and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.belladonna and opiumMonitor Closely (1)belladonna and opium and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.benperidolMonitor Closely (3)oxybutynin decreases levels of benperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of benperidol by pharmacodynamic antagonism. Use Caution/Monitor. benperidol increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.benztropineMonitor Closely (1)benztropine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. bethanecholMonitor Closely (1)bethanechol increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.bosentanMinor (1)bosentan will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.budesonideMinor (1)budesonide will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.butabarbitalMinor (1)butabarbital will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.butalbitalMinor (1)butalbital will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.carbacholMonitor Closely (1)carbachol increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.carbamazepineMonitor Closely (2)oxybutynin will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor plasma levels when used concomitantly carbamazepine will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.cenobamateMonitor Closely (1)cenobamate, oxybutynin. Either increases effects of the other by sedation. Use Caution/Monitor.cevimelineMonitor Closely (1)cevimeline increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpromazineMonitor Closely (3)oxybutynin decreases levels of chlorpromazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of chlorpromazine by pharmacodynamic antagonism. Use Caution/Monitor. chlorpromazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin increases toxicity of chlorpromazine by unspecified interaction mechanism. Minor/Significance Unknown.cimetidineMonitor Closely (1)cimetidine will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.cisatracuriumMonitor Closely (1)cisatracurium and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.clarithromycinMonitor Closely (1)clarithromycin will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.clomipramineMonitor Closely (1)oxybutynin and clomipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.clozapineMonitor Closely (3)oxybutynin decreases levels of clozapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of clozapine by pharmacodynamic antagonism. Use Caution/Monitor. clozapine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.conivaptanMinor (1)conivaptan will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cortisoneMinor (1)cortisone will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cyclizineMonitor Closely (1)cyclizine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.cyclobenzaprineMonitor Closely (1)cyclobenzaprine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.daridorexantMonitor Closely (1)oxybutynin and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. darifenacinMonitor Closely (1)darifenacin and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.Minor (1)darifenacin will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.darunavirMinor (1)darunavir will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.dasatinibMinor (1)dasatinib will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.deferasiroxMinor (1)deferasirox will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.desipramineMonitor Closely (1)oxybutynin and desipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.dexamethasoneMinor (1)dexamethasone will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.DHEA, herbalMinor (1)DHEA, herbal will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.dicyclomineMonitor Closely (1)dicyclomine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.difelikefalinMonitor Closely (1)difelikefalin and oxybutynin both increase sedation. Use Caution/Monitor.digoxinMinor (1)oxybutynin increases levels of digoxin by unspecified interaction mechanism. Minor/Significance Unknown.diltiazemMonitor Closely (1)diltiazem will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dimenhydrinateMinor (1)dimenhydrinate increases toxicity of oxybutynin by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.diphenhydramineMonitor Closely (1)diphenhydramine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.donepezilMonitor Closely (1)donepezil increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)donepezil decreases effects of oxybutynin by pharmacodynamic antagonism. Minor/Significance Unknown.donepezil transdermalMonitor Closely (1)donepezil transdermal, oxybutynin. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dosulepinMonitor Closely (1)oxybutynin and dosulepin both decrease cholinergic effects/transmission. Use Caution/Monitor.doxepinMonitor Closely (1)oxybutynin and doxepin both decrease cholinergic effects/transmission. Use Caution/Monitor.dronedaroneMinor (1)dronedarone will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.droperidolMonitor Closely (3)oxybutynin decreases levels of droperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of droperidol by pharmacodynamic antagonism. Use Caution/Monitor. droperidol increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.echothiophate iodideMonitor Closely (1)echothiophate iodide increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.efavirenzMinor (1)efavirenz will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.erythromycin baseMonitor Closely (1)erythromycin base will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin ethylsuccinateMonitor Closely (1)erythromycin ethylsuccinate will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin lactobionateMonitor Closely (1)erythromycin lactobionate will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin stearateMonitor Closely (1)erythromycin stearate will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.eslicarbazepine acetateMinor (1)eslicarbazepine acetate will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.etravirineMinor (1)etravirine will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fesoterodineMonitor Closely (1)fesoterodine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.finerenoneMonitor Closely (1)oxybutynin will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.flavoxateMonitor Closely (1)flavoxate and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.flibanserinMonitor Closely (1)oxybutynin will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.fluconazoleMinor (1)fluconazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fludrocortisoneMinor (1)fludrocortisone will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fluphenazineMonitor Closely (3)oxybutynin decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor. fluphenazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.fosamprenavirMinor (1)fosamprenavir will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fosaprepitantMinor (1)fosaprepitant will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.fosphenytoinMinor (1)fosphenytoin will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.galantamineMonitor Closely (1)galantamine increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)galantamine decreases effects of oxybutynin by pharmacodynamic antagonism. Minor/Significance Unknown.glycopyrrolateMonitor Closely (1)glycopyrrolate and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.glycopyrrolate inhaledMonitor Closely (1)glycopyrrolate inhaled and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.grapefruitMinor (1)grapefruit will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.griseofulvinMinor (1)griseofulvin will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.haloperidolMonitor Closely (3)oxybutynin decreases effects of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor. oxybutynin decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. haloperidol increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.henbaneMonitor Closely (1)henbane and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.homatropineMonitor Closely (1)homatropine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.huperzine AMonitor Closely (1)huperzine A increases and oxybutynin decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydrocortisoneMinor (1)hydrocortisone will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.hyoscyamineMonitor Closely (1)hyoscyamine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.hyoscyamine sprayMonitor Closely (1)hyoscyamine spray and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.iloperidoneMonitor Closely (3)oxybutynin decreases levels of iloperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of iloperidone by pharmacodynamic antagonism. Use Caution/Monitor. iloperidone increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.imipramineMonitor Closely (1)oxybutynin and imipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.indinavirMinor (1)indinavir will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ipratropiumMonitor Closely (1)ipratropium and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor. Due to the poor systemic absorption of ipratropium, interaction unlikely at regularly recommended dosages.isavuconazonium sulfateMonitor Closely (1)oxybutynin will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoniazidMinor (1)isoniazid will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.itraconazoleMonitor Closely (1)itraconazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ivacaftorMonitor Closely (1)oxybutynin increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .ketoconazoleMonitor Closely (1)ketoconazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lapatinibMinor (1)lapatinib will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lemborexantMonitor Closely (1)oxybutynin will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.letermovirMonitor Closely (1)letermovir increases levels of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.levodopaMinor (1)oxybutynin, levodopa. Other (see comment). Minor/Significance Unknown. Comment: Anticholinergic agents may enhance the therapeutic effects of levodopa; however, anticholinergic agents can exacerbate tardive dyskinesia. In high dosage, anticholinergics may decrease the effects of levodopa by delaying its GI absorption. .levoketoconazoleMonitor Closely (1)levoketoconazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lofepramineMonitor Closely (1)oxybutynin and lofepramine both decrease cholinergic effects/transmission. Use Caution/Monitor.lomitapideMonitor Closely (1)oxybutynin increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.lonafarnibSerious - Use Alternative (1)oxybutynin will increase