effects/transmission. Use Caution/Monitor.prednisoneprednisone will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.primidoneprimidone will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prochlorperazinetolterodine decreases levels of prochlorperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of prochlorperazine by pharmacodynamic antagonism. Use Caution/Monitor.prochlorperazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.promethazinetolterodine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.promethazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.propafenonepropafenone will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Use caution when prescribing propafenone concurrently with tolterodine. Concomitant use of propafenone and tolterodine may cause QT prolongation. propanthelinepropantheline and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.protriptylinetolterodine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.pyridostigminepyridostigmine increases and tolterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.quetiapinetolterodine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.quetiapine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.quinidinequinidine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.quinupristin/dalfopristinquinupristin/dalfopristin will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rapacuroniumrapacuronium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.rifapentinerifapentine will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.risperidonetolterodine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.risperidone increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.ritonavirritonavir will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rivastigminetolterodine and rivastigmine both decrease cholinergic effects/transmission. Use Caution/Monitor.rocuroniumrocuronium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.rolapitantrolapitant will increase the level or effect of tolterodine 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.rucaparibrucaparib will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.rufinamiderufinamide will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.scopolaminescopolamine and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.secobarbitalsecobarbital will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.solifenacinsolifenacin and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.stiripentolstiripentol, tolterodine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.succinylcholinesuccinylcholine increases and tolterodine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.tazemetostattazemetostat will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimattecovirimat will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.terbinafineterbinafine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.thioridazinetolterodine decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.thiothixenetolterodine decreases levels of thiothixene by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of thiothixene by pharmacodynamic antagonism. Use Caution/Monitor.thiothixene increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.tiotropiumtiotropium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.topiramatetopiramate will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.trazodonetolterodine and trazodone both decrease cholinergic effects/transmission. Use Caution/Monitor.trifluoperazinetolterodine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.trihexyphenidyltolterodine and trihexyphenidyl both decrease cholinergic effects/transmission. Use Caution/Monitor. Potential for additive anticholinergic effects.trimipraminetolterodine and trimipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.trospium chloridetolterodine and trospium chloride both decrease cholinergic effects/transmission. Use Caution/Monitor.vecuroniumtolterodine and vecuronium both decrease cholinergic effects/transmission. Use Caution/Monitor.verapamilverapamil will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.voriconazolevoriconazole will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.zafirlukastzafirlukast will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ziprasidonetolterodine decreases levels of ziprasidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of ziprasidone by pharmacodynamic antagonism. Use Caution/Monitor.ziprasidone increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.zotepinetolterodine decreases levels of zotepine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of zotepine by pharmacodynamic antagonism. Use Caution/Monitor.Minor (31)acetazolamideacetazolamide will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amiodaroneamiodarone will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.anastrozoleanastrozole will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.asenapineasenapine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.celecoxibcelecoxib will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.chloroquinechloroquine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cimetidinecimetidine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.darifenacindarifenacin will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.dimenhydrinatedimenhydrinate increases toxicity of tolterodine by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.diphenhydraminediphenhydramine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.donepezildonepezil decreases effects of tolterodine by pharmacodynamic antagonism. Minor/Significance Unknown.dronedaronedronedarone will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.duloxetineduloxetine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.galantaminegalantamine decreases effects of tolterodine by pharmacodynamic antagonism. Minor/Significance Unknown.haloperidolhaloperidol will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.imatinibimatinib will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.larotrectiniblarotrectinib will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.levodopatolterodine, 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. .maravirocmaraviroc will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.marijuanamarijuana will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.nilotinibnilotinib will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.parecoxibparecoxib will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.perphenazineperphenazine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.quinacrinequinacrine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.ranolazineranolazine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.ritonavirritonavir will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.sertralinesertraline will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.thioridazinethioridazine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.tipranavirtipranavir will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.venlafaxinevenlafaxine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.abametapirSerious - Use Alternative (1)abametapir will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.abirateroneMonitor Closely (1)abiraterone increases levels of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.abobotulinumtoxinAMonitor Closely (1)abobotulinumtoxinA increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects. .acetazolamideMinor (1)acetazolamide will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aclidiniumMonitor Closely (1)aclidinium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.amantadineMonitor Closely (1)tolterodine, amantadine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Potential for increased anticholinergic adverse effects.amiodaroneMinor (1)amiodarone will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.amitriptylineMonitor Closely (1)tolterodine and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.amobarbitalMonitor Closely (1)amobarbital will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.amoxapineMonitor Closely (1)tolterodine and amoxapine both decrease cholinergic effects/transmission. Use Caution/Monitor.anastrozoleMinor (1)anastrozole will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.anticholinergic/sedative combosMonitor Closely (1)anticholinergic/sedative combos and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.apalutamideSerious - Use Alternative (1)apalutamide will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.aprepitantMonitor Closely (1)aprepitant will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.aripiprazoleMonitor Closely (3)tolterodine decreases levels of aripiprazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. tolterodine decreases levels of aripiprazole by pharmacodynamic antagonism. Use Caution/Monitor. aripiprazole increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.armodafinilMonitor Closely (1)armodafinil will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.artemether/lumefantrineMonitor Closely (2)artemether/lumefantrine will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. artemether/lumefantrine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.asenapineMinor (1)asenapine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.atazanavirMonitor Closely (1)atazanavir will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.atracuriumMonitor Closely (1)atracurium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.atropineMonitor Closely (1)atropine and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.atropine IV/IMMonitor Closely (1)atropine IV/IM and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.belladonna alkaloidsMonitor Closely (1)belladonna alkaloids and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.belladonna and opiumMonitor Closely (1)belladonna and opium and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.benperidolMonitor Closely (3)tolterodine decreases levels of benperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. tolterodine decreases levels of benperidol by pharmacodynamic antagonism. Use Caution/Monitor. benperidol increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.benztropineMonitor Closely (1)benztropine and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. bethanecholMonitor Closely (1)bethanechol increases and tolterodine 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 tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.budesonideMonitor Closely (1)budesonide will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.bupropionMonitor Closely (1)bupropion will increase the level or effect of tolterodine