Tadalafil
Pronunciation: (see-AL-iss) (ta-DA-la-fil).
- Generic name
- tadalafil
- Brand names
- Tadacip, Forzest, Tadalis, Cialis, Megalis, Adcirca
- Drug class
- Phosphodiesterase type 5 (PDE5) inhibitor
Availability and supply rules vary by country
Trade names by country: United States · Canada
Australia: · Full directory
What tadalafil is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how tadalafil works
Tadalafil is a selective inhibitor of phosphodiesterase type 5 (PDE5). By inhibiting PDE5, tadalafil increases cyclic guanosine monophosphate (cGMP) levels in the corpus cavernosum, resulting in smooth muscle relaxation and increased blood flow to the penis during sexual stimulation. In the lower urinary tract, it relaxes smooth muscle in the prostate and bladder, improving BPH symptoms. For PAH, it dilates pulmonary vasculature, reducing pulmonary vascular resistance. (1)
What tadalafil is used for
Erectile Dysfunction
Erectile Dysfunction (2)
Pulmonary Arterial Hypertension
Pulmonary Arterial Hypertension (2)
Benign prostatic hyperplasia (BPH) signs and symptoms, alone or together with ED
Benign prostatic hyperplasia (BPH) signs and symptoms, alone or together with ED (2)
Before taking tadalafil
Do not take / not appropriate for
- Contraindicated in patients using nitrates, those with hypersensitivity to tadalafil, severe hepatic impairment, recent stroke or myocardial infarction, unstable angina, or severe hypotension. (Contraindication) (2)
Tell your clinician about
(2)How to take tadalafil
- General Instructions: Take Cialis exactly as prescribed by your healthcare provider. Do not take more than one dose per day.. Adult Dosing: For erectile dysfunction: 10 mg taken prior to anticipated sexual activity, or 2.5-5 mg once daily. For BPH: 5 mg once daily. For PAH (Adcirca): 40 mg once daily.. Pediatric Dosing: Cialis is not approved for use in children or adolescents.. Administration: Swallow the tablet whole with water, with or without food. Take at the same time each day if prescribed for daily use.. When To Stop: Seek medical attention promptly if you experience serious side effects, allergic reactions, or if your condition worsens; let the clinician you see advise on whether to continue or stop Cialis.. Storage: Store at room temperature (20-25°C/68-77°F), away from moisture and heat. Keep out of reach of children.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)
Missed dose
If you miss a dose and take Cialis daily, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not double up to make up for a missed dose.
Overdose
In case of overdose, seek emergency medical attention or call your local poison control center. Symptoms may include severe dizziness, fainting, or a prolonged erection. (2)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Headache
Incidence: As-needed use: ~15%; once-daily use: 3-6%
Dyspepsia (indigestion)
Incidence: As-needed use: ~10%; once-daily use: 3-5%
Back pain
Incidence: As-needed use: ~6%; once-daily use: ~3%
Muscle aches (myalgia)
Incidence: As-needed use: 3-4%
Nasal congestion, flushing, or pain in a limb
Incidence: As-needed use: ~3% each
Upper respiratory tract infection
Incidence: Once-daily use: ~3%
An erection lasting more than 4 hours (priapism)
(1)Sudden vision loss or sudden hearing loss/ringing in the ears
(2)Signs of a serious skin reaction (e.g., widespread rash or skin peeling) — rare hypersensitivity reactions including Stevens-Johnson syndrome and exfoliative dermatitis have been reported
(2)Serious warnings
Do not use with nitrates due to risk of severe hypotension — serious
Symptoms: Do not use with nitrates due to risk of severe hypotension. Not recommended for individuals with severe heart or liver impairment. May cause vision or hearing loss in rare cases. Use caution in patients with anatomical deformation of the penis or predisposition to priapism. May interact with other medications, including alpha-blockers and antihypertensives.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindicated in patients using nitrates, those with hypersensitivity to tadalafil, severe hepatic impairment, recent stroke or myocardial infarction, unstable angina, or severe hypotension. Use caution in patients with renal or hepatic impairment, anatomical penile deformation, or predisposition to priapism.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Sudden vision loss — serious
Symptoms: Sudden vision loss: seek medical attention immediately if sudden loss of vision occurs in one or both eyes — this may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent vision loss; let the clinician you see advise on whether to continue or stop Cialis and other PDE5 inhibitors. Sudden hearing loss: seek prompt medical attention if you have a sudden decrease or loss of hearing, which may be accompanied by ringing in the ears (tinnitus) or dizziness; again, let the clinician you see advise on continuing or stopping treatment.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Cialis can interact with nitrates, alpha-blockers, antihypertensive drugs, certain antifungals (e.g., ketoconazole), antibiotics (e.g., erythromycin), HIV protease inhibitors, and grapefruit products. These interactions may increase the risk of side effects or reduce the effectiveness of the medication. Always inform your healthcare provider of all medications and supplements you are taking. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Cialis (tadalafil) is not indicated for use in women. There are no adequate and well-controlled studies of Cialis use in pregnant women. (2)
Breastfeeding
Cialis (tadalafil) is not indicated for use in women. It is not known whether tadalafil passes into human milk. (2)
Children
Frequency: Not applicable. Weight Based: Not recommended for pediatric use. Max Daily Dose: Not applicable. Max Single Dose: Not applicable. Age Restrictions: Safety not established in children (2)
Renal_impairment
Renal impairment (as-needed dosing): mild (CrCl 51-80 mL/min) no adjustment; moderate (CrCl 31-50 mL/min) maximum 5 mg once daily, or maximum 10 mg not more than once every 48 hours; severe (CrCl <30 mL/min) or on hemodialysis, maximum 5 mg not more than once every 72 hours. For once-daily dosing, severe renal impairment is not recommended. Hepatic impairment (as-needed dosing): mild-to-moderate (Child-Pugh A or B) dose should not exceed 10 mg once per day; severe (Child-Pugh C) use is not recommended. For once-daily dosing, mild-to-moderate hepatic impairment requires caution; severe hepatic impairment is not recommended. (2)
Hepatic_impairment
Renal impairment (as-needed dosing): mild (CrCl 51-80 mL/min) no adjustment; moderate (CrCl 31-50 mL/min) maximum 5 mg once daily, or maximum 10 mg not more than once every 48 hours; severe (CrCl <30 mL/min) or on hemodialysis, maximum 5 mg not more than once every 72 hours. For once-daily dosing, severe renal impairment is not recommended. Hepatic impairment (as-needed dosing): mild-to-moderate (Child-Pugh A or B) dose should not exceed 10 mg once per day; severe (Child-Pugh C) use is not recommended. For once-daily dosing, mild-to-moderate hepatic impairment requires caution; severe hepatic impairment is not recommended. (2)
Monitoring
(2)Storage
Requires a primary-source research pass before this section can be completed.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: Erectile Dysfunction
Dose summary: For erectile dysfunction, the recommended starting dose is 10 mg taken prior to sexual activity. For pulmonary arterial hypertension, the recommended dose is 40 mg taken once daily.
Renal context: Moderate renal impairment: maximum 5 mg once daily (as-needed dosing). Severe renal impairment/hemodialysis: maximum 5 mg not more than once every 72 hours; once-daily dosing not recommended. (1) (2)
Frequently asked questions
How long does Cialis take to work?
Cialis usually starts working within 30 to 60 minutes after taking the tablet. Its effects can last up to 36 hours, allowing for more flexibility in timing sexual activity.
Can I take Cialis every day?
Yes, Cialis can be prescribed as a daily low-dose tablet (2.5-5 mg) for erectile dysfunction or BPH. Follow your doctor's instructions for daily use.
Is Cialis safe for people with heart problems?
Cialis should not be used by people taking nitrates or with certain heart conditions. Always consult your doctor before use if you have a history of heart disease.
What should I do if I get an erection lasting more than 4 hours?
Seek immediate medical attention. A prolonged erection (priapism) can cause permanent damage if not treated promptly.
Can women use Cialis?
Cialis is not approved for use in women for sexual dysfunction. It may be prescribed for pulmonary arterial hypertension under the brand Adcirca.
Can I drink alcohol while taking Cialis?
Limit alcohol consumption while taking Cialis, as excessive drinking can increase the risk of side effects such as low blood pressure, dizziness, and headache.
Does Cialis protect against sexually transmitted infections?
No, Cialis does not protect against HIV or other sexually transmitted infections. Use appropriate protection if needed.
What happens if I take too much Cialis (tadalafil)?
Taking too much Cialis (tadalafil) can lead to an overdose, potentially causing severe side effects such as priapism (prolonged erection), severe hypotension, or vision changes. If you suspect an overdose, it is crucial to seek immediate emergency medical attention. Do not attempt to self-treat an overdose.
Can I drink alcohol while taking Cialis (tadalafil)?
Drinking alcohol while taking Cialis (tadalafil) is generally not recommended. Both alcohol and tadalafil can lower blood pressure, and combining them may lead to excessive drops in blood pressure, causing dizziness, lightheadedness, headaches, and fainting. It's best to limit or avoid alcohol consumption.
Is Cialis (tadalafil) safe during pregnancy?
Cialis (tadalafil) is not indicated for use in women at all — it is approved only for men (erectile dysfunction, BPH) and, under the brand Adcirca, for pulmonary arterial hypertension in adults generally. The FDA label states there are no adequate and well-controlled studies of Cialis in pregnant women. It does not use an old-style pregnancy letter category.
What is the mechanism of action of tadalafil?
Tadalafil is a selective inhibitor of phosphodiesterase type 5 (PDE5). By inhibiting PDE5, tadalafil increases cyclic guanosine monophosphate (cGMP) levels in the corpus cavernosum, resulting in smooth muscle relaxation and increased blood flow to the penis during sexual stimulation. In the lower urinary tract, it relaxes smooth muscle in the prostate and bladder, improving BPH symptoms. For PAH, it dilates pulmonary vasculature, reducing pulmonary vascular resistance. (1)
What is the generic name of Tadalafil?
The generic name is tadalafil. It is sold under brand names including Tadacip, Forzest, Tadalis, Cialis, Megalis, Adcirca.
What class of drug is tadalafil?
Tadalafil is classed as: Phosphodiesterase type 5 (PDE5) inhibitor.
References
- MedGuideGlobal clinician-authored medicine record – Cialis (tadalafil)MedGuideGlobal · United States · accessed 2026-08-06 · source 1
- CIALIS (tadalafil) full prescribing informationU.S. Food and Drug Administration / DailyMed · United States · accessed 2026-08-06 · source 2
- TADALAFIL TABLET [NUCARE PHARMACEUTICALS,INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
- Tadalafil — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
- tadalafil — FDA approval record (Drugs@FDA ANDA215556)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 5
- tadalafil — RxNorm normalized drug concept (RXCUI 358263)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 6
Brand names by country
Single-ingredient tadalafil names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Cialis10 mg, 20 mg, 5 mg · eli lilly and company
- TADLIQ20 mg/5mL · cmp pharma, inc.
- ALYQ20 mg · teva pharmaceuticals, inc.
- ADCIRCA20 mg · united therapeutics corporation
Canada
- CIALIS
- ADCIRCA
- APO-TADALAFIL PAH