based on tolerability.Serious - Use Alternative (1)atazanavir will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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 based on tolerability.atenololMonitor Closely (1)tadalafil increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.azilsartanMonitor Closely (1)tadalafil increases effects of azilsartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.benazeprilMonitor Closely (1)tadalafil increases effects of benazepril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.betaxololMonitor Closely (1)tadalafil increases effects of betaxolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.bicalutamideMonitor Closely (1)bicalutamide 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. bisoprololMonitor Closely (1)tadalafil increases effects of bisoprolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.bosentanMonitor Closely (1)bosentan will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.budesonideMonitor Closely (1)budesonide will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.bumetanideMonitor Closely (1)tadalafil increases effects of bumetanide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.butabarbitalMonitor Closely (1)butabarbital 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.butalbitalMonitor Closely (1)butalbital will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.candesartanMonitor Closely (1)tadalafil increases effects of candesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.captoprilMonitor Closely (1)tadalafil increases effects of captopril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.carbamazepineMonitor Closely (1)carbamazepine 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.carvedilolMonitor Closely (1)tadalafil increases effects of carvedilol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.cenobamateMonitor Closely (1)cenobamate 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.ceritinibSerious - Use Alternative (1)ceritinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.chlorthalidoneMonitor Closely (1)tadalafil increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.cimetidineMonitor Closely (1)cimetidine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.clarithromycinSerious - Use Alternative (1)clarithromycin will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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.clevidipineMonitor Closely (1)tadalafil increases effects of clevidipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.clonidineMonitor Closely (1)tadalafil increases effects of clonidine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.clotrimazoleMonitor Closely (1)clotrimazole 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. cobicistatSerious - Use Alternative (1)cobicistat will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Adjust tadalafil dose for PAH; if on cobicistat, start tadalafil 20 mg/day and may increase up to 40 mg/day; avoid tadalafil when starting cobicistat; for ED, may take a single dose of tadalafil not exceeding 10 mg in 72 hr.conivaptanMonitor Closely (1)conivaptan 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.crizotinibMonitor Closely (1)crizotinib 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.crofelemerMonitor Closely (1)crofelemer 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.cyclophosphamideMinor (1)cyclophosphamide will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cyclosporineMonitor Closely (1)cyclosporine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dabrafenibMonitor Closely (1)dabrafenib will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.darunavirSerious - Use Alternative (1)darunavir will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Adjust tadalafil dose for PAH; if on cobicistat, start tadalafil 20 mg/day and may increase up to 40 mg/day; avoid tadalafil when starting cobicistat; for ED, may take a single dose of tadalafil not exceeding 10 mg in 72 hr.dasatinibMonitor Closely (1)dasatinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.deferasiroxMonitor Closely (1)deferasirox will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dexamethasoneMonitor Closely (1)dexamethasone 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.diltiazemMonitor Closely (1)diltiazem will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Risk of hypotension.doxazosinMonitor Closely (1)tadalafil increases effects of doxazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.dronedaroneMonitor Closely (1)dronedarone will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.duvelisibMonitor Closely (1)duvelisib 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.efavirenzMonitor Closely (1)efavirenz 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.elagolixMonitor Closely (1)elagolix 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 DFMonitor Closely (1)elvitegravir/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.enalaprilMonitor Closely (1)tadalafil increases effects of enalapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.encorafenibMonitor Closely (1)encorafenib, 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.enzalutamideSerious - Use Alternative (1)enzalutamide will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eplerenoneMonitor Closely (1)tadalafil increases effects of eplerenone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.eprosartanMonitor Closely (1)tadalafil increases effects of eprosartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.erythromycin baseSerious - Use Alternative (1)erythromycin base will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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.erythromycin ethylsuccinateSerious - Use Alternative (1)erythromycin ethylsuccinate will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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.erythromycin lactobionateSerious - Use Alternative (1)erythromycin lactobionate will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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.erythromycin stearateSerious - Use Alternative (1)erythromycin stearate will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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.eslicarbazepine acetateMonitor Closely (1)eslicarbazepine 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.esmololMonitor Closely (1)tadalafil increases effects of esmolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ethacrynic acidMonitor Closely (1)tadalafil increases effects of ethacrynic acid by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ethanolMonitor Closely (1)ethanol, tadalafil. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Combination may increase risk of orthostatic hypotension, tachycardia, dizziness and headache.etravirineMonitor Closely (1)etravirine will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fedratinibMonitor Closely (1)fedratinib 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.felodipineMonitor Closely (1)tadalafil increases effects of felodipine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.fexinidazoleSerious - Use Alternative (1)fexinidazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.fluconazoleMonitor Closely (1)fluconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluvoxamineMonitor Closely (1)fluvoxamine will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosamprenavirSerious - Use Alternative (1)fosamprenavir will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. 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 based on tolerability.fosaprepitantMonitor Closely (1)fosaprepitant will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosinoprilMonitor Closely (1)tadalafil increases effects of fosinopril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.fosphenytoinMonitor Closely (1)fosphenytoin 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.furosemideMonitor Closely (1)tadalafil increases effects of furosemide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.grapefruitMonitor Closely (1)grapefruit will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.griseofulvinMonitor Closely (1)griseofulvin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.guanfacineMonitor Closely (1)tadalafil increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.haloperidolMonitor Closely (1)haloperidol 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. hydralazineMonitor Closely (1)tadalafil increases effects of hydralazine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.hydrochlorothiazideMonitor Closely (1)tadalafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.idelalisibSerious - Use Alternative (1)idelalisib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substratesiloperidoneMonitor Closely (1)iloperidone increases levels of tadalafil