Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ENTADFI vs CIALIS
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.
Phosphodiesterase-5 (PDE5) inhibitor; increases c GMP levels, causing smooth muscle relaxation and vasodilation in the corpus cavernosum, enhancing erectile function.
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,Treatment of benign prostatic hyperplasia,Treatment of pulmonary arterial hypertension (as Adcirca)
5 mg orally once daily.
Tadalafil 10 mg or 20 mg orally as needed at least 30 minutes before sexual activity; maximum dosing frequency once daily. Alternative: 2.5 mg or 5 mg once daily for daily use.
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.
The terminal elimination half-life of tadalafil is approximately 17.5 hours in healthy subjects, which supports once-daily dosing for erectile dysfunction and once-daily use for benign prostatic hyperplasia. This long half-life distinguishes it from other PDE5 inhibitors.
Finasteride is metabolized primarily via CYP3A4. Tadalafil is metabolized mainly by CYP3A4.
Primarily hepatic via CYP3A4; minor pathways include CYP2C9 and glucuronidation.
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.
Following oral administration, tadalafil is predominantly eliminated by hepatic metabolism. The metabolites are excreted mainly in feces (approximately 61% of the dose) and to a lesser extent in urine (approximately 36% of the dose). No unchanged parent drug is detected in urine.
Finasteride: ~90% bound to plasma proteins (mainly albumin). Tadalafil: ~94% bound to plasma proteins (mainly albumin).
Tadalafil is 94% bound to plasma proteins, primarily to albumin. The protein binding is independent of drug concentration over a wide range.
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.
The apparent volume of distribution (Vd/F) is approximately 63 L (or roughly 0.9 L/kg for a 70 kg individual), indicating distribution into tissues beyond the vascular space, including the penis and other target organs.
Finasteride 5 mg: oral bioavailability ~63% (range 56-74%). Tadalafil 5 mg: oral bioavailability ~80% (relative to intravenous); absorption not affected by food.
Absolute oral bioavailability of tadalafil has not been formally determined; however, the drug is well absorbed after oral administration, with peak plasma concentrations reached in 0.5 to 6 hours (median 2 hours). Food does not affect the extent of absorption (AUC), though it may delay the rate (Tmax) by about 1–2 hours.
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).
Cr Cl 30-50 m L/min: 5 mg once daily (max) for daily use; as-needed dosing: 10 mg not to exceed once every 48 hours. Cr Cl <30 m L/min: not recommended. Hemodialysis: not studied.
Contraindicated in Child-Pugh class B and C hepatic impairment. No dose adjustment required for Child-Pugh class A.
Child-Pugh A and B: no dose adjustment necessary for as-needed dosing; daily use: caution, start at 5 mg once daily. Child-Pugh C: not recommended.
Not approved for use in pediatric patients.
Not indicated for pediatric patients under 18 years.
No specific dose adjustment required; however, monitor for adverse effects due to potential age-related renal and hepatic decline.
No dose adjustment required solely based on age; consider renal function and concomitant medications.
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
Risk of hypotension with vasodilators or alpha-blockers,Contraindicated with nitrates due to severe hypotension risk,Patients with left ventricular outflow obstruction (e.g., aortic stenosis) should avoid use,Caution in patients with hypotension, severe hepatic impairment, or end-stage renal disease,Risk of priapism: advise immediate medical attention for erections lasting >4 hours,Decreased visual or hearing ability requiring discontinuation
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 nitrates (any form) or riociguat,Hypersensitivity to tadalafil,Concomitant use with alpha-blockers (except for BPH with appropriate dosing)
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.
Avoid high-fat meals prior to dosing as they may delay absorption and reduce peak plasma concentration. Avoid large quantities of grapefruit juice (more than 1 liter per day) as it may increase tadalafil exposure via CYP3A4 inhibition.
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.
FDA Pregnancy Category B. Animal studies show no evidence of teratogenicity or embryotoxicity. No adequate, well-controlled studies in pregnant women. 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.
Excretion in human milk unknown. Not recommended for use in nursing mothers. M/P ratio not determined.
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 studied in pregnancy. Use lowest effective dose if necessary, with caution for increased plasma volume and renal clearance potentially altering pharmacokinetics.
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.
Tadalafil (Cialis) has a 17.5-hour half-life allowing once-daily dosing for ED or daily for BPH/LUTS. Avoid use with nitrates; may cause prolonged erection. Onset of action is 30-60 minutes, and effect may last up to 36 hours. Use with caution in patients with left ventricular outflow obstruction or severe hepatic impairment.
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.
Do not take tadalafil if you take any form of nitrate medication (e.g., nitroglycerin) for chest pain.,Seek immediate medical help if you have an erection lasting more than 4 hours.,Avoid alcohol consumption as it may increase the risk of dizziness and low blood pressure.,Take tadalafil at least 30 minutes before sexual activity; effect can last up to 36 hours.,For daily use, take at the same time each day without regard to timing of sexual activity.,Grapefruit and grapefruit juice may increase tadalafil levels; avoid large amounts.,Inform your doctor of all medications you take, especially alpha-blockers, antihypertensives, and antifungal or antibiotic drugs.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ENTADFI vs CIALIS, 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.. CIALIS is a PDE5 Inhibitor that works by Phosphodiesterase-5 (PDE5) inhibitor; increases c GMP levels, causing smooth muscle relaxation and vasodilation in the corpus cavernosum, enhancing erectile function.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ENTADFI and CIALIS 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 CIALIS is: Tadalafil 10 mg or 20 mg orally as needed at least 30 minutes before sexual activity; maximum dosing frequency once daily. Alternative: 2.5 mg or 5 mg once daily for daily use.. 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 CIALIS 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. CIALIS is classified as Category C. FDA Pregnancy Category B. Animal studies show no evidence of teratogenicity or embryotoxicity. No adequate, well-controlled studies in pregnant women. Risk cannot be ruled out; use. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.