effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.pazopanibMonitor Closely (1)pazopanib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.penbutololMonitor Closely (1)tadalafil increases effects of penbutolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.pentobarbitalMonitor Closely (1)pentobarbital 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.Minor (1)pentobarbital will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.phenobarbitalMonitor Closely (1)phenobarbital 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.Minor (1)phenobarbital will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.phenoxybenzamineMonitor Closely (1)tadalafil increases effects of phenoxybenzamine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.phentolamineMonitor Closely (1)tadalafil increases effects of phentolamine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.phenytoinMonitor Closely (1)phenytoin 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.Minor (1)phenytoin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.posaconazoleMonitor Closely (1)posaconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)posaconazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.prazosinMonitor Closely (1)tadalafil increases effects of prazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.prednisoneMinor (1)prednisone will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.primidoneMonitor Closely (1)primidone 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.Minor (1)primidone will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.propranololMonitor Closely (1)tadalafil increases effects of propranolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.quinaprilMonitor Closely (1)tadalafil increases effects of quinapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.quinupristin/dalfopristinMonitor Closely (1)quinupristin/dalfopristin will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)quinupristin/dalfopristin will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ramiprilMonitor Closely (1)tadalafil increases effects of ramipril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.ranolazineMinor (1)ranolazine 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.ribociclibMonitor Closely (1)ribociclib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifabutinMonitor Closely (2)rifabutin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. rifabutin 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.rifampinMonitor Closely (2)rifampin 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. rifampin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifapentineMonitor Closely (1)rifapentine 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.Minor (1)rifapentine will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.riociguatContraindicated (1)tadalafil, riociguat. Either increases effects of the other by additive vasodilation. Contraindicated. Coadministration of PDE-5 inhibitors (eg, avanafil, sildenafil, tadalafil, vardenafil) and guanylate cyclase stimulators (eg, riociguat) is contraindicated due to risk of additive hypotension; do not administer 24 hr before or within 48hr of each other.ritonavirSerious - Use Alternative (1)ritonavir 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.Minor (1)ritonavir will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.rucaparibMonitor Closely (1)rucaparib 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.rufinamideMonitor Closely (1)rufinamide will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)rufinamide will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sacubitril/valsartanMonitor Closely (1)tadalafil increases effects of sacubitril/valsartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.sapropterinMonitor Closely (1)sapropterin, tadalafil. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Possible additive vasorelaxation, leading to low blood pressure.saquinavirMonitor Closely (1)saquinavir increases levels of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .saw palmettoMinor (1)saw palmetto increases effects of finasteride by pharmacodynamic synergism. Minor/Significance Unknown.secobarbitalMonitor Closely (1)secobarbital 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.Minor (1)secobarbital will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sertralineMonitor Closely (1)sertraline 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. silodosinMonitor Closely (1)tadalafil increases effects of silodosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.sotalolMonitor Closely (1)tadalafil increases effects of sotalol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.spironolactoneMonitor Closely (1)tadalafil increases effects of spironolactone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.St John's WortMonitor Closely (1)St 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.stiripentolMonitor Closely (1)stiripentol, 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.tamsulosinMonitor Closely (1)tadalafil, tamsulosin. Either increases effects of the other by additive vasodilation. Use Caution/Monitor. Risk of hypotension.tazemetostatMonitor Closely (1)tazemetostat will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimatMonitor Closely (1)tecovirimat 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.telmisartanMonitor Closely (1)tadalafil increases effects of telmisartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.terazosinMonitor Closely (1)tadalafil increases effects of terazosin by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.tetracyclineMonitor Closely (1)tetracycline 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. timololMonitor Closely (1)tadalafil increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.tipranavirMonitor Closely (1)tipranavir 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 inhaledMonitor Closely (1)tobramycin inhaled and tadalafil both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicitytopiramateMonitor Closely (1)topiramate will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)topiramate will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.torsemideMonitor Closely (1)tadalafil increases effects of torsemide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.trandolaprilMonitor Closely (1)tadalafil increases effects of trandolapril by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.triamtereneMonitor Closely (1)tadalafil increases effects of triamterene by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.tucatinibSerious - Use Alternative (1)tucatinib will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.valsartanMonitor Closely (1)tadalafil increases effects of valsartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.vardenafilMonitor Closely (1)vardenafil, tadalafil. Other (see comment). Use Caution/Monitor. Comment: Avoid combination; duplicate therapy is not recommended.verapamilMonitor Closely (1)verapamil will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Risk of hypotension.Minor (1)verapamil will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.vericiguatContraindicated (1)tadalafil, vericiguat. Either increases effects of the other by pharmacodynamic synergism. Contraindicated. Coadministration of vericiguat with PDE-5 inhibitors may result in additive hypotensive effects.voriconazoleMonitor Closely (1)voriconazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)voriconazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.voxelotorSerious - Use Alternative (1)voxelotor will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.zafirlukastMonitor Closely (1)zafirlukast will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)zafirlukast will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. >10% Finasteride Impotence (5.1-18.5%) 1-10% Finasteride Decreased libido (2.6-10%) Postural hypotension (9.1%) Dizziness (7.4%) Abnormal ejaculation (7.2%) Asthenia (5.3%) Decreased ejaculate volume (1.5-3.7%) Sexual function abnormal (2.5%) Gynecomastia (2.2%) Headache (2%) Breast enlargement (0.5-1.8%) Somnolence (1.7%) Peripheral edema (1.3%) Hypotension (1.2%) Rhinitis (1%) Tadalafil Headache (4.1%) Dyspepsia (2.4%) Back pain (2.4%) Nasopharyngitis (2.1%) Diarrhea (1.4%) Pain in extremity (1.4%) Myalgia (1.2%) Dizziness (1%) <2% (uncertain causality) Body as a whole: Asthenia, face edema, fatigue, pain, peripheral edema Cardiovascular: Angina pectoris, chest pain, hypotension, myocardial infarction, postural hypotension, palpitations, syncope, tachycardia Digestive: Abnormal liver function tests, dry mouth, dysphagia, esophagitis, gastritis, gamma-glutamyl transpeptidase (GGTP) increased, loose stools, nausea, upper abdominal pain, vomiting, gastroesophageal reflux disease, hemorrhoidal hemorrhage, rectal hemorrhage Musculoskeletal: Arthralgia, neck pain Nervous: Dizziness, hypoesthesia, insomnia, paresthesia, somnolence, vertigo Renal and urinary: Renal impairment Respiratory: Dyspnea, epistaxis, pharyngitis Skin and appendages: Pruritus, rash, sweating Ophthalmologic: Blurred vision, changes in color vision, conjunctivitis (including conjunctival hyperemia), eye pain, lacrimation increase, swelling of eyelids Otologic: Sudden decrease in or loss of hearing, tinnitus Urogenital: Erection increased, spontaneous penile erection <1% Finasteride Ejaculation disorder (0.2-0.8%) Dyspnea (0.7%) Breast tenderness (0.4-0.7%) Rash (0.5%) Postmarketing Reports Finasteride Hypersensitivity reactions (eg, pruritus, urticaria, angioedema [including swelling of lips, tongue, throat, and face]) Testicular pain Hematospermia Sexual dysfunction that continued after discontinuation of treatment Male infertility and/or poor seminal quality Depression Male breast cancer Tadalafil Cardiovascular and cerebrovascular: Serious cardiovascular events, including myocardial infarction, sudden cardiac death, stroke, chest pain, palpitations, and tachycardia Body as a whole: Hypersensitivity reactions including urticaria, Stevens-Johnson syndrome, and exfoliative dermatitis Nervous: Migraine, seizure and seizure recurrence, transient global amnesia Ophthalmologic: Visual-field defect, retinal vein occlusion, retinal artery occlusion nonarteritic anterior ischemic optic neuropathy Otologic: Sudden decrease in or loss of hearing Urogenital: Priapism Contraindications Known hypersensitivity to finasteride, tadalafil, or capsule components; hypersensitivity reactions have included Stevens-Johnson syndrome, exfoliative dermatitis, pruritus, urticaria, and angioedema Pregnancy Coadministration with nitrates or soluble guanylate cyclase (sGC) stimulators (eg, riociguat) Cautions Hypersensitivity reported; contraindicated with history of hypersensitivity to finasteride, tadalafil, or capsule components; discontinue immediately if hypersensitivity occurs Before initiating, rule out other urologic conditions that may cause similar symptoms; prostate cancer and BPH may