of hypotension.bosentanbosentan will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.budesonidebudesonide will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.bumetanidetadalafil increases effects of bumetanide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.butabarbitalbutabarbital will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.butalbitalbutalbital will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.candesartantadalafil increases effects of candesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.captopriltadalafil increases effects of captopril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.carbamazepinecarbamazepine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.carbamazepine will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.carvediloltadalafil increases effects of carvedilol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.clarithromycinclarithromycin will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.cenobamatecenobamate will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.chlorthalidonetadalafil increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.cimetidinecimetidine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.clevidipinetadalafil increases effects of clevidipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.clonidinetadalafil increases effects of clonidine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.clotrimazoleclotrimazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events. conivaptanconivaptan will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.crizotinibcrizotinib increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.crofelemercrofelemer increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.cyclosporinecyclosporine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dabrafenibdabrafenib will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.dasatinibdasatinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.deferasiroxdeferasirox will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dexamethasonedexamethasone will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.diltiazemdiltiazem will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Risk of hypotension.doxazosintadalafil increases effects of doxazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.dronedaronedronedarone will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.duvelisibduvelisib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.efavirenzefavirenz will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.elagolixelagolix decreases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.elvitegravir/cobicistat/emtricitabine/tenofovir DFelvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tadalafil dose for PAH; if on Stribild, start tadalafil 20 mg/day; avoid tadalafil when starting Stribild; for ED, a single dose of tadalafil not exceeding 10 mg in 72 hr.enalapriltadalafil increases effects of enalapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.encorafenibencorafenib, tadalafil. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.eplerenonetadalafil increases effects of eplerenone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.eprosartantadalafil increases effects of eprosartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.erythromycin baseerythromycin base will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin ethylsuccinateerythromycin ethylsuccinate will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin lactobionateerythromycin lactobionate will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.erythromycin stearateerythromycin stearate will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.eslicarbazepine acetateeslicarbazepine acetate will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.esmololtadalafil increases effects of esmolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ethacrynic acidtadalafil increases effects of ethacrynic acid by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ethanolethanol, tadalafil. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Combination may increase risk of orthostatic hypotension, tachycardia, dizziness and headache.etravirineetravirine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fedratinibfedratinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.felodipinetadalafil increases effects of felodipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.fluconazolefluconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluvoxaminefluvoxamine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosaprepitantfosaprepitant will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosinopriltadalafil increases effects of fosinopril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.fosphenytoinfosphenytoin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.furosemidetadalafil increases effects of furosemide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.grapefruitgrapefruit will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.griseofulvingriseofulvin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.guanfacinetadalafil increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.haloperidolhaloperidol will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events. hydralazinetadalafil increases effects of hydralazine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.hydrochlorothiazidetadalafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.iloperidoneiloperidone increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.imatinibimatinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.indapamidetadalafil increases effects of indapamide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.irbesartantadalafil increases effects of irbesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.isoniazidisoniazid will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoniazid will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.isradipinetadalafil increases effects of isradipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.itraconazoleitraconazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.istradefyllineistradefylline will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.ketoconazoleketoconazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.labetaloltadalafil increases effects of labetalol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.lapatiniblapatinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.letermovirletermovir increases levels of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.letermovir increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.levoketoconazolelevoketoconazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lisinopriltadalafil increases effects of lisinopril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.losartantadalafil increases effects of losartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.lumefantrinelumefantrine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.maravirocmaraviroc, tadalafil. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.marijuanamarijuana will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.metolazonetadalafil increases effects of metolazone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.metoprololtadalafil increases effects of metoprolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.metronidazolemetronidazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.mifepristonemifepristone will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.minoxidiltadalafil increases effects of minoxidil by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.mitotanemitotane decreases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.nadololtadalafil increases effects of nadolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.nafcillinnafcillin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nebivololtadalafil increases effects of nebivolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.nefazodonenefazodone will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nefazodone will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.nevirapinenevirapine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.nevirapine will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nifedipinenifedipine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Risk of hypotension.tadalafil increases effects of nifedipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.rifabutinrifabutin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nilotinibnilotinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nimodipinetadalafil increases effects of nimodipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.nisoldipinetadalafil increases effects of nisoldipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.nitroprusside sodiumnitroprusside sodium, tadalafil. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects.olmesartantadalafil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.oxcarbazepineoxcarbazepine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.