Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ENTADFI vs AVANAFIL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
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.
Selective inhibitor of phosphodiesterase type 5 (PDE5), enhancing nitric oxide-mediated relaxation of smooth muscle in the corpus cavernosum, increasing c GMP levels, and promoting penile erection.
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
Treatment of erectile dysfunction (FDA-approved),Pulmonary arterial hypertension (off-label)
5 mg orally once daily.
100 mg orally once daily, taken 30-60 minutes before sexual activity. Maximum dosing frequency: once daily.
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.
Terminal elimination half-life approximately 6-8 hours. Clinical context: Supports once-daily dosing; steady-state reached within 5 days with no accumulation at FDA-approved dose.
Finasteride is metabolized primarily via CYP3A4. Tadalafil is metabolized mainly by CYP3A4.
Primarily metabolized by CYP3A4, with minor contributions from CYP2C9 and CYP2C19. Subject to first-pass metabolism.
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.
Primarily hepatic metabolism via CYP3A4 and CYP2C9, with metabolites excreted in feces (approximately 82-90%) and urine (approximately 6-8% as unchanged drug and minor metabolites).
Finasteride: ~90% bound to plasma proteins (mainly albumin). Tadalafil: ~94% bound to plasma proteins (mainly albumin).
Approximately 99% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein.
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.
Volume of distribution approximately 200 L (≈ 2.9 L/kg for a 70 kg individual). Clinical meaning: Indicates extensive tissue distribution, with high affinity for genital tissues.
Finasteride 5 mg: oral bioavailability ~63% (range 56-74%). Tadalafil 5 mg: oral bioavailability ~80% (relative to intravenous); absorption not affected by food.
Oral bioavailability approximately 15-20% due to extensive first-pass metabolism. Absolute bioavailability not determined in humans; based on animal data.
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).
No dosage adjustment required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). Not recommended for severe renal impairment (Cr Cl <30 m L/min) as safety and efficacy have not been established.
Contraindicated in Child-Pugh class B and C hepatic impairment. No dose adjustment required for Child-Pugh class A.
Child-Pugh Class A and B: No dosage adjustment required. Child-Pugh Class C: Not recommended due to lack of data.
Not approved for use in pediatric patients.
Not indicated for use in pediatric patients (age <18 years). Safety and efficacy not established.
No specific dose adjustment required; however, monitor for adverse effects due to potential age-related renal and hepatic decline.
No dosage adjustment required solely based on age. However, consider lower starting dose (50 mg) in patients ≥65 years due to potential increased sensitivity and decreased clearance.
No FDA black box warning.
None.
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
Cardiovascular risk: Not recommended in patients with unstable angina, recent MI (within 90 days), or uncontrolled arrhythmias.,Hypotension: Caution with alpha-blockers or antihypertensives; avoid in those with hypotension (BP <90/50 mm Hg).,Priapism: Advise patients to seek immediate medical attention for erections lasting >4 hours.,Hepatic impairment: Avoid use in severe hepatic impairment (Child-Pugh class C).,Renal impairment: Not recommended in patients on renal dialysis.,Visual effects: Non-arteritic anterior ischemic optic neuropathy (NAION) reported, though rare.
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)
Concomitant use of organic nitrates (e.g., nitroglycerin, isosorbide mononitrate/dinitrate),Concomitant use of guanylate cyclase stimulators (e.g., riociguat),Hypersensitivity to avanafil or any component of the formulation,Severe hepatic impairment (Child-Pugh class C),Recent stroke or myocardial infarction (within 6 months),Patients with hypotension (BP <90/50 mm Hg)
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.
Avanafil can be taken with or without food. However, a high-fat meal may delay absorption and reduce peak plasma concentration, potentially prolonging time to onset. Grapefruit juice may increase avanafil levels; avoid concurrent consumption.
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.
No adequate and well-controlled studies in pregnant women. Animal studies show no evidence of teratogenicity at exposures up to 18 times the MRHD. Risk cannot be ruled out; use only if clearly needed.
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.
Not known if excreted in human milk. No data on M/P ratio. Caution advised; consider developmental benefits of breastfeeding vs potential adverse effects.
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.
No specific dose adjustments established; use lowest effective dose if indicated. Pharmacokinetic changes in pregnancy unknown; monitor for efficacy and adverse effects.
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.
Avanafil is a rapid-onset PDE5 inhibitor with a Tmax of 30-45 minutes, making it suitable for on-demand use. It has minimal interaction with alpha-blockers compared to other PDE5 inhibitors, but caution is still advised. Avoid use in patients taking nitrates or those with severe hepatic impairment (Child-Pugh C). Its short half-life (5 hours) reduces the duration of side effects like headache and flushing.
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.
Take avanafil approximately 30 minutes before sexual activity, with or without food.,Do not take more than one dose in a 24-hour period.,Seek emergency medical attention if you experience an erection lasting more than 4 hours (priapism) or sudden vision loss.,Avoid alcohol or limit to small amounts as it may increase side effects like dizziness or hypotension.,Inform your doctor if you are taking any medications, especially nitrates, alpha-blockers, or antihypertensives.
No interactions on record
"Avanafil, a phosphodiesterase type 5 (PDE5) inhibitor, enhances the vasodilatory effects of nitric oxide by increasing cyclic guanosine monophosphate (cGMP) levels. Acebutolol, a cardioselective beta-blocker, reduces cardiac output and sympathetic outflow. Concurrent use may lead to additive hypotension, particularly during initiation or dose escalation, potentially causing dizziness, syncope, or orthostatic hypotension."
"Cobicistat is a potent inhibitor of CYP3A4, the primary enzyme responsible for metabolizing avanafil. Co-administration significantly increases avanafil's systemic exposure, potentially doubling its plasma concentration and half-life. This elevated exposure raises the risk of avanafil-associated adverse effects, such as hypotension, priapism, and visual disturbances, and may also enhance cobicistat's own serum levels due to shared metabolic pathways, increasing the likelihood of nephrotoxicity and other protease inhibitor-related toxicities."
"Isavuconazonium is a prodrug of isavuconazole, a triazole antifungal that inhibits CYP3A4 and CYP3A5. Coadministration with avanafil, a PDE5 inhibitor metabolized primarily by CYP3A4, can increase avanafil exposure due to reduced clearance. This may elevate the risk of avanafil-associated adverse effects such as hypotension, priapism, and visual disturbances."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ENTADFI vs AVANAFIL, answered by our medical review team.
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.. AVANAFIL is a PDE5 Inhibitor that works by Selective inhibitor of phosphodiesterase type 5 (PDE5), enhancing nitric oxide-mediated relaxation of smooth muscle in the corpus cavernosum, increasing c GMP levels, and promoting penile erection.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ENTADFI and AVANAFIL 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 ENTADFI is: 5 mg orally once daily.. The standard adult dose of AVANAFIL is: 100 mg orally once daily, taken 30-60 minutes before sexual activity. Maximum dosing frequency: 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 ENTADFI and AVANAFIL 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. 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. AVANAFIL is classified as Category C. No adequate and well-controlled studies in pregnant women. Animal studies show no evidence of teratogenicity at exposures up to 18 times the MRHD. Risk cannot be ruled out; use onl. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.