Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CIALIS vs ADCIRCA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Phosphodiesterase-5 (PDE5) inhibitor; increases c GMP levels, causing smooth muscle relaxation and vasodilation in the corpus cavernosum, enhancing erectile function.
Phosphodiesterase-5 (PDE5) inhibitor; increases c GMP in pulmonary vascular smooth muscle, leading to vasodilation.
Treatment of erectile dysfunction,Treatment of benign prostatic hyperplasia,Treatment of pulmonary arterial hypertension (as Adcirca)
Treatment of pulmonary arterial hypertension (PAH) (WHO Group I) to improve exercise capacity and delay clinical worsening.,Off-label: Erectile dysfunction (not FDA-approved for this indication in the context of PAH).
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.
10 mg orally three times daily.
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.
Terminal half-life: 10–15 hours in healthy adults; prolonged in hepatic impairment (Child-Pugh B/C: up to 30 hours); clinical context: supports twice-daily dosing
Primarily hepatic via CYP3A4; minor pathways include CYP2C9 and glucuronidation.
Primarily metabolized by CYP3A4 (major) and CYP2C9 (minor) hepatic enzymes.
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.
Renal: ~70% (metabolites and unchanged drug), Fecal: ~20%, Biliary: minor
Tadalafil is 94% bound to plasma proteins, primarily to albumin. The protein binding is independent of drug concentration over a wide range.
96% bound to albumin and alpha-1-acid glycoprotein
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.
Vd: 0.4–0.7 L/kg; suggests distribution into total body water and moderate tissue binding
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.
Oral: 80%; absolute bioavailability: 50% due to first-pass metabolism
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.
No dose adjustment required for mild to moderate renal impairment; avoid use in severe impairment (Cr Cl <30 m L/min) due to lack of data.
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.
Mild to moderate hepatic impairment (Child-Pugh A or B): 10 mg orally once daily; severe hepatic impairment (Child-Pugh C): contraindicated.
Not indicated for pediatric patients under 18 years.
Not established for patients <18 years.
No dose adjustment required solely based on age; consider renal function and concomitant medications.
No specific dose adjustment, but caution due to increased sensitivity; monitor renal function.
None
Do not use in patients taking nitrates (regularly or intermittently) due to risk of severe hypotension.
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
Risk of hypotension, especially with nitrates or alpha-blockers.,Hematologic effects: increased risk of bleeding due to antiplatelet activity; caution with bleeding disorders or anticoagulants.,Vision loss: non-arteritic anterior ischemic optic neuropathy (NAION) has been reported; discontinue if sudden vision loss occurs.,Hearing loss: sudden decrease or loss of hearing; may be accompanied by tinnitus or dizziness.,Use caution in patients with left ventricular outflow obstruction (e.g., aortic stenosis) or severely impaired autonomic control of blood pressure.,Dose adjustment required with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir).
Concomitant use of nitrates (any form) or riociguat,Hypersensitivity to tadalafil,Concomitant use with alpha-blockers (except for BPH with appropriate dosing)
Concomitant use of nitrates (any form) or nitric oxide donors.,Concomitant use with riociguat or other guanylate cyclase stimulators.,Known hypersensitivity to tadalafil or any component of the product.,Severe hepatic impairment (Child-Pugh class C).
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.
Avoid grapefruit and grapefruit juice as they may increase tadalafil levels and risk of side effects. No other significant food interactions. High-fat meals may delay absorption but do not require dose adjustment.
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.
Pregnancy Category B. Animal studies have not demonstrated fetal risk, but there are no adequate and well-controlled studies in pregnant women. First trimester: risk cannot be ruled out; use only if clearly needed. Second and third trimesters: no known fetal risks, but caution advised due to maternal hypotension risk.
Excretion in human milk unknown. Not recommended for use in nursing mothers. M/P ratio not determined.
Not recommended. Excretion in human milk unknown. M/P ratio not established. Risk of hypotension in neonate. Alternative feeding method advised during therapy and for 48 hours after last dose.
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.
No specific pharmacokinetic data in pregnancy. Standard dose (40 mg orally once daily) recommended. Monitor for hypotension; dose adjustment not routinely required unless maternal hypotension develops.
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.
Adcirca (tadalafil) is a PDE5 inhibitor indicated for pulmonary arterial hypertension (PAH) to improve exercise ability. It is dosed at 40 mg once daily, not as needed. Avoid use with nitrates due to risk of severe hypotension. Monitor for vision loss (non-arteritic anterior ischemic optic neuropathy) and hearing loss. Use caution in patients with hepatic impairment (Child-Pugh class B: reduce dose; class C: contraindicated). Dose adjustment required with potent CYP3A4 inhibitors (e.g., ketoconazole: reduce to 20 mg). Not recommended for severe renal impairment (Cr Cl <30 m L/min) or on hemodialysis.
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.
Take Adcirca exactly as prescribed, 40 mg once daily, at the same time each day. Do not take it as needed for erectile dysfunction.,Do not take Adcirca if you are taking any form of nitrate medication (e.g., nitroglycerin) or recreational drugs called 'poppers' (amyl nitrate) as this can cause a sudden dangerous drop in blood pressure.,Seek immediate medical attention if you experience sudden vision loss or decrease in hearing, as these may be signs of a serious side effect.,Avoid drinking large amounts of alcohol (e.g., 3 or more drinks) within a short time while taking Adcirca, as it may increase the risk of dizziness, lightheadedness, and fainting.,Inform your healthcare provider about all medications you take, including prescription, over-the-counter, and herbal products, especially alpha-blockers, erythromycin, or ritonavir.,Adcirca may cause dizziness. Do not drive or operate machinery until you know how the medicine affects you.
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 CIALIS vs ADCIRCA, answered by our medical review team.
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.. ADCIRCA is a PDE5 Inhibitor that works by Phosphodiesterase-5 (PDE5) inhibitor; increases c GMP in pulmonary vascular smooth muscle, leading to vasodilation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CIALIS and ADCIRCA depend on the specific clinical indication. These are both PDE5 Inhibitor agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
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.. The standard adult dose of ADCIRCA is: 10 mg orally three times 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 CIALIS and ADCIRCA 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. 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. ADCIRCA is classified as Category C. Pregnancy Category B. Animal studies have not demonstrated fetal risk, but there are no adequate and well-controlled studies in pregnant women. First trimester: risk cannot be rule. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.