Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
FINASTERIDE AND TADALAFIL vs ENTADFI
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Finasteride is a 5α-reductase inhibitor that inhibits conversion of testosterone to dihydrotestosterone (DHT). Tadalafil is a phosphodiesterase-5 (PDE5) inhibitor that enhances nitric oxide-mediated vasodilation by increasing cyclic guanosine monophosphate (c GMP) in smooth muscle.
Combination of a 5α-reductase inhibitor (finasteride) and a phosphodiesterase 5 inhibitor (tadalafil). Finasteride inhibits type II 5α-reductase, preventing conversion of testosterone to dihydrotestosterone, reducing prostate growth. Tadalafil inhibits PDE5, increasing c GMP in smooth muscle, causing relaxation of the prostate and bladder neck.
Treatment of benign prostatic hyperplasia (BPH)
Treatment of signs and symptoms of benign prostatic hyperplasia (BPH),Treatment of BPH in men with an enlarged prostate to improve symptoms, reduce risk of acute urinary retention, and reduce need for surgery
One capsule containing finasteride 5 mg and tadalafil 5 mg orally once daily.
5 mg orally once daily.
Finasteride: 6-8 hours (elderly ~8 hours); Tadalafil: 17.5 hours (enables once-daily dosing).
Finasteride: terminal half-life ~6-8 hours (range 4-12 h) in young adults, 8 hours in elderly. Tadalafil: terminal half-life ~17.5 hours (range 11-28 h), supporting once-daily dosing.
Finasteride is extensively metabolized in the liver via CYP3A4; tadalafil is primarily metabolized by CYP3A4.
Finasteride is metabolized primarily via CYP3A4. Tadalafil is metabolized mainly by CYP3A4.
Finasteride: 57% feces, 39% urine (metabolites); Tadalafil: 36% urine, 61% feces (mostly metabolites).
ENTADFI (finasteride 5 mg and tadalafil 5 mg) is a fixed-dose combination. Finasteride is excreted 57% in feces (as metabolites) and 39% in urine (<1% as unchanged). Tadalafil is excreted primarily as metabolites, with 61% in feces and 36% in urine; <0.001% of dose is excreted unchanged in urine.
Finasteride: 90% bound to albumin and alpha-1-acid glycoprotein; Tadalafil: 94% bound to albumin.
Finasteride: ~90% bound to plasma proteins (mainly albumin). Tadalafil: ~94% bound to plasma proteins (mainly albumin).
Finasteride: 76 L/kg (1.1 L/kg in elderly); Tadalafil: 63-77 L/kg (extensive tissue distribution).
Finasteride: Vd ≈ 76 L (approx 1.1 L/kg based on 70 kg). Tadalafil: Vd ≈ 63-77 L (approx 0.9-1.1 L/kg), indicating extensive tissue distribution.
Finasteride: 63% oral (80% relative to IV); Tadalafil: 80% oral (bioavailability unaffected by food).
Finasteride 5 mg: oral bioavailability ~63% (range 56-74%). Tadalafil 5 mg: oral bioavailability ~80% (relative to intravenous); absorption not affected by food.
No adjustment for mild-moderate renal impairment (Cr Cl ≥30 m L/min). Avoid in severe renal impairment (Cr Cl <30 m L/min) or on dialysis due to increased tadalafil exposure.
No dose adjustment required for mild to moderate renal impairment. Not recommended in severe renal impairment (e GFR <30 m L/min/1.73 m²).
Child-Pugh A: no adjustment. Child-Pugh B: limit tadalafil dose to 5 mg (same as given); use caution. Child-Pugh C: avoid use.
Contraindicated in Child-Pugh class B and C hepatic impairment. No dose adjustment required for Child-Pugh class A.
Not indicated in pediatric patients; safety and efficacy not established.
Not approved for use in pediatric patients.
No dose adjustment required; monitor for orthostatic hypotension and dizziness, as elderly may be more sensitive to vasodilatory effects.
No specific dose adjustment required; however, monitor for adverse effects due to potential age-related renal and hepatic decline.
There is no FDA black box warning for the combination product. Individual components have warnings: Finasteride exposure during pregnancy may cause abnormalities of male external genitalia; Tadalafil is contraindicated in patients taking guanylate cyclase stimulators (e.g., riociguat) and nitrates.
No FDA black box warning.
Risk of priapism (tadalafil); sudden hearing loss (tadalafil); orthostatic hypotension with concomitant antihypertensives; prostate-specific antigen (PSA) level reduction (finasteride); risk of high-grade prostate cancer (finasteride); use in women of childbearing potential (finasteride teratogenicity).
Hypersensitivity reactions,Sudden decrease in hearing or tinnitus,Prostate cancer screening and monitoring,Cardiovascular risk with sexual activity,Contraindicated with organic nitrates and GC stimulators (e.g., riociguat),Risk of priapism,Hepatic impairment dose adjustment,Renal impairment dose adjustment,Use of alpha-blockers,Antihypertensive effects,Risk of hypotension with concomitant alcohol
Hypersensitivity to finasteride or tadalafil; concurrent use of nitrates or guanylate cyclase stimulators (e.g., riociguat); women who are or may become pregnant (finasteride teratogenicity).
Hypersensitivity to finasteride, tadalafil, or any component,Concurrent use of any organic nitrate,Concurrent use of guanylate cyclase stimulators (e.g., riociguat),Women, especially during pregnancy (finasteride teratogenicity)
Avoid grapefruit and grapefruit juice as they increase tadalafil plasma concentrations. Alcohol may potentiate hypotension and dizziness. High-fat meals may delay tadalafil absorption but do not reduce efficacy.
Grapefruit juice may increase tadalafil plasma concentrations; avoid concurrent consumption. High-fat meals may delay tadalafil absorption but do not affect overall exposure. There are no significant food interactions with finasteride.
Finasteride: Contraindicated in pregnancy due to risk of hypospadias in male fetuses (Category X). Tadalafil: Category B; no fetal harm in animal studies, but insufficient human data. Avoid combination in pregnant women.
ENTADFI (finasteride and tadalafil) is contraindicated in pregnancy. Finasteride is a 5α-reductase inhibitor that inhibits conversion of testosterone to dihydrotestosterone (DHT) and can cause abnormal development of external genitalia in male fetuses. First trimester exposure is associated with hypospadias and other genital malformations. There is no human data for second and third trimester; however, based on mechanism, risks persist throughout pregnancy. Tadalafil, a PDE5 inhibitor, is Pregnancy Category B; no fetal harm is known in animals, but human data are limited.
Finasteride: Excreted in breast milk (M/P ratio unknown); not recommended. Tadalafil: Presence in breast milk unknown; avoid due to potential adverse effects.
No data available on ENTADFI (finasteride/tadalafil) in human milk. Finasteride is excreted in rat milk, but M/P ratio is unknown. Tadalafil is excreted in animal milk; M/P ratio unknown. Due to potential for adverse effects on lactating infant, especially from finasteride (possible interference with androgen metabolism), breastfeeding is not recommended during treatment and for at least 1 month after last dose.
Contraindicated in pregnancy; pharmacokinetic changes in pregnancy do not apply as use is not recommended. No dose adjustment applicable.
ENTADFI is contraindicated in pregnancy; no dosing adjustments are recommended because use is not permitted. If inadvertently administered, discontinue immediately. There are no established pharmacokinetic changes in pregnancy for finasteride or tadalafil; however, pregnancy-induced changes in drug metabolism are not expected to alter the need for dose adjustment because the drug is not used during gestation.
Finasteride and tadalafil combination is used for benign prostatic hyperplasia (BPH). Tadalafil may cause priapism; advise immediate medical attention for erections lasting >4 hours. Finasteride decreases serum PSA by ~50%; double PSA values for interpretation. Avoid coadministration with strong CYP3A4 inhibitors (e.g., ketoconazole) due to increased tadalafil exposure. Tadalafil is contraindicated with nitrates due to severe hypotension. Assess cardiovascular stability before prescribing tadalafil.
ENTADFI (finasteride and tadalafil fixed-dose combination) is used for benign prostatic hyperplasia (BPH). Finasteride reduces DHT, improving symptoms and reducing risk of acute urinary retention; tadalafil enhances smooth muscle relaxation via PDE5 inhibition. Monitor PSA levels during therapy (finasteride halves PSA). Assess cardiovascular status before initiating tadalafil; avoid concurrent nitrates. Caution in hepatic impairment (tadalafil exposure increased). Advise patients that therapeutic effect may take 3-6 months.
Take the medication at the same time daily with or without food.,Seek emergency care for erections lasting longer than 4 hours.,Inform your doctor about all medications, especially nitrates or alpha-blockers.,Finasteride may reduce PSA levels; do not stop taking before PSA testing without consulting your doctor.,Avoid grapefruit juice as it may increase side effects.,Tadalafil may cause dizziness or syncope; avoid driving if affected.
Take ENTADFI at the same time daily with or without food.,Do not take more than one dose per day.,Avoid grapefruit juice as it may increase tadalafil levels.,Report sudden decrease in hearing or vision promptly.,Seek immediate medical help for erection lasting >4 hours.,Use contraception if partner is pregnant or may become pregnant (finasteride can cause fetal harm).,Do not donate blood during treatment and for 1 month after stopping.,Avoid alcohol excessively as it may increase risk of hypotension.
"Tadalafil, a phosphodiesterase-5 (PDE5) inhibitor, potentiates the hypotensive effect of trandolapril, an angiotensin-converting enzyme (ACE) inhibitor, by enhancing cyclic guanosine monophosphate (cGMP)-mediated vasodilation. This additive hemodynamic effect can lead to symptomatic hypotension, particularly in patients with volume depletion, pre-existing low blood pressure, or those on multiple antihypertensives. Clinically, this interaction manifests as a risk of excessive blood pressure reduction, especially when tadalafil is taken within 4-6 hours of trandolapril administration."
"Posaconazole, an azole antifungal, is a potent inhibitor of CYP3A4, while tadalafil is a CYP3A4 substrate. Coadministration significantly increases tadalafil exposure, leading to elevated risk of adverse effects such as hypotension, syncope, and priapism. The interaction is well-documented and requires dose adjustment or avoidance."
"Tadalafil, a phosphodiesterase-5 (PDE5) inhibitor, potentiates the vasoconstrictive and hypertensive effects of xylometazoline, an alpha-1 adrenergic receptor agonist. This occurs through tadalafil's inhibition of cGMP degradation in vascular smooth muscle, which counteracts the normal nitric oxide-mediated vasodilation and enhances the pressor response to alpha-agonists. Clinically, this interaction can lead to excessive and prolonged increases in blood pressure, potentially resulting in hypertensive crisis, especially in patients with underlying cardiovascular conditions."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about FINASTERIDE AND TADALAFIL vs ENTADFI, answered by our medical review team.
FINASTERIDE AND TADALAFIL is a PDE5 Inhibitor that works by Finasteride is a 5α-reductase inhibitor that inhibits conversion of testosterone to dihydrotestosterone (DHT). Tadalafil is a phosphodiesterase-5 (PDE5) inhibitor that enhances nitric oxide-mediated vasodilation by increasing cyclic guanosine monophosphate (c GMP) in smooth muscle.. ENTADFI is a 5-Alpha Reductase Inhibitor and PDE5 Inhibitor that works by Combination of a 5α-reductase inhibitor (finasteride) and a phosphodiesterase 5 inhibitor (tadalafil). Finasteride inhibits type II 5α-reductase, preventing conversion of testosterone to dihydrotestosterone, reducing prostate growth. Tadalafil inhibits PDE5, increasing c GMP in smooth muscle, causing relaxation of the prostate and bladder neck.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between FINASTERIDE AND TADALAFIL and ENTADFI depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of FINASTERIDE AND TADALAFIL is: One capsule containing finasteride 5 mg and tadalafil 5 mg orally once daily.. The standard adult dose of ENTADFI is: 5 mg orally once daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between FINASTERIDE AND TADALAFIL and ENTADFI in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. FINASTERIDE AND TADALAFIL is classified as Category A/B. Finasteride: Contraindicated in pregnancy due to risk of hypospadias in male fetuses (Category X). Tadalafil: Category B; no fetal harm in animal studies, but insufficient human da. ENTADFI is classified as Category C. ENTADFI (finasteride and tadalafil) is contraindicated in pregnancy. Finasteride is a 5α-reductase inhibitor that inhibits conversion of testosterone to dihydrotestosterone (DHT) a. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.