reduction of sensitive CYP3A4 substrates.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 tadalafil 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 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.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.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. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.pazopanibpazopanib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.penbutololtadalafil increases effects of penbutolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.pentobarbitalpentobarbital 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.phenobarbitalphenobarbital 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.phenoxybenzaminetadalafil increases effects of phenoxybenzamine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.phentolaminetadalafil increases effects of phentolamine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.phenytoinphenytoin 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.posaconazoleposaconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prazosintadalafil increases effects of prazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.primidoneprimidone 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.propranololtadalafil increases effects of propranolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.quinapriltadalafil increases effects of quinapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.quinupristin/dalfopristinquinupristin/dalfopristin will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ramipriltadalafil increases effects of ramipril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ribociclibribociclib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifabutinrifabutin 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.rifampinrifampin 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.rifapentinerifapentine 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.rucaparibrucaparib will increase the level or effect of tadalafil 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 tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.sacubitril/valsartantadalafil increases effects of sacubitril/valsartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.sapropterinsapropterin, tadalafil. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Possible additive vasorelaxation, leading to low blood pressure.saquinavirsaquinavir increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .secobarbitalsecobarbital 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.sertralinesertraline 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. silodosintadalafil increases effects of silodosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.sotaloltadalafil increases effects of sotalol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.spironolactonetadalafil increases effects of spironolactone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.St John's WortSt John's Wort 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.stiripentolstiripentol, tadalafil. 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.tamsulosintadalafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.tazemetostattazemetostat will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimattecovirimat will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.telmisartantadalafil increases effects of telmisartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.terazosintadalafil increases effects of terazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.tetracyclinetetracycline 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. timololtadalafil increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.tipranavirtipranavir 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.tobramycin inhaledtobramycin inhaled and tadalafil both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicitytopiramatetopiramate will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.torsemidetadalafil increases effects of torsemide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.trandolapriltadalafil increases effects of trandolapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.triamterenetadalafil increases effects of triamterene by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.valsartantadalafil increases effects of valsartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.vardenafilvardenafil, tadalafil. Other (see comment). Use Caution/Monitor. Comment: Avoid combination; duplicate therapy is not recommended.verapamilverapamil will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Risk of hypotension.voriconazolevoriconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.zafirlukastzafirlukast will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (5)acetazolamideacetazolamide will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.anastrozoleanastrozole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.larotrectiniblarotrectinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ranolazineranolazine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Ranolazine may theoretically increase plasma concentrations of CYP3A4 substrates, such as tadalafil.abametapirSerious - Use Alternative (1)abametapir will increase the level or effect of tadalafil 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.acebutololMonitor Closely (1)tadalafil increases effects of acebutolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.acetazolamideMonitor Closely (1)tadalafil increases effects of acetazolamide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.Minor (1)acetazolamide will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.alfuzosinMonitor Closely (1)tadalafil increases effects of alfuzosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.aliskirenMonitor Closely (1)tadalafil increases effects of aliskiren by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.amifostineMonitor Closely (1)amifostine, tadalafil. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Monitor blood pressure response to phosphodiesterase type 5 (PDE5) inhibitors in patients receiving concurrent blood pressure lowering therapy.amilorideMonitor Closely (1)tadalafil increases effects of amiloride by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.amiodaroneMonitor Closely (1)amiodarone will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events. amlodipineMonitor Closely (1)tadalafil increases effects of amlodipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.amobarbitalMonitor Closely (1)amobarbital will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.amyl nitriteSerious - Use Alternative (1)amyl nitrite, tadalafil. Mechanism: additive vasodilation. Avoid or Use Alternate Drug. Contraindicated. Potentially fatal hypotension. Allow 48h after last tadalafil dose before nitrate administration.anastrozoleMinor (1)anastrozole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apalutamideSerious - Use Alternative (1)apalutamide will decrease the level or effect of tadalafil 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 tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.armodafinilMonitor Closely (1)armodafinil will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.artemether/lumefantrineMonitor Closely (1)artemether/lumefantrine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.asenapineMonitor Closely (1)tadalafil increases effects of asenapine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.atazanavirMonitor Closely (1)atazanavir increases levels of tadalafil by decreasing metabolism. Use Caution/Monitor. Stop tadalafil >24 hours prior to protease inhibitor (PI) initiation, restart 7 days after PI initiation at 20 mg once daily, and increase to 40 mg once daily