Cialis (Tadalafil)
Cialis is a prescription medication containing tadalafil, a long-acting PDE5 inhibitor used by adult men with erectile dysfunction. Tablets come in 2.5mg, 5mg, 10mg and 20mg, supporting both on-demand and daily dosing schedules.
- Active ingredients
- Tadalafil
- Manufacturer
- Eli Lilly
- Dosage forms
- tablet
- Available dosages
- 2.5mg, 5mg, 10mg, 20mg
- Category
- Erectile Dysfunction (ED)
What is it?
Cialis is the original brand name for tadalafil, an oral medication first approved in 2003 for the treatment of erectile dysfunction in adult men. It is manufactured by Eli Lilly and is one of the most widely studied PDE5 inhibitors. The drug does not cause an erection on its own — sexual stimulation is required — and is available only on prescription in most countries. Cialis is also approved for benign prostatic hyperplasia and pulmonary arterial hypertension at adapted doses.
Active ingredients
Each tablet contains tadalafil as the active ingredient, supplied in four commercial strengths: 2.5mg, 5mg, 10mg and 20mg. The 2.5mg and 5mg presentations are designed for once-daily dosing; 10mg and 20mg are intended for on-demand use before planned sexual activity. As a selective PDE5 inhibitor, tadalafil produces a longer effect window than other molecules in the class thanks to a 17.5-hour half-life.
Forms and dosages
Cialis is supplied as almond-shaped, yellow, film-coated tablets. For on-demand use, the typical adult starting dose is 10mg taken at least 30 minutes before planned sexual activity, with adjustment to 5mg or 20mg by a prescribing physician. For daily use, the starting dose is 5mg taken at the same time each day, with possible reduction to 2.5mg. Maximum on-demand frequency is one dose per 24 hours. Tablets can be taken with or without food.
Indications
Cialis is indicated in adult men for the treatment of erectile dysfunction. It is also approved for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia, with the dual indication treated using the daily 5mg formulation. The medication is not approved for women, paediatric patients or men without a relevant diagnosis. According to the manufacturer's prescribing information, treatment should follow assessment of cardiovascular fitness and current medications.
How it works
During sexual stimulation, nitric oxide is released in the corpus cavernosum and activates an enzyme that produces cyclic GMP. Cyclic GMP relaxes smooth muscle in the penile arteries and increases blood flow to support an erection. Tadalafil prevents PDE5 from breaking down cyclic GMP, prolonging its action. Onset is typically within 30 to 60 minutes after an on-demand dose, with effects lasting up to 36 hours according to clinical trials — the longest window among approved PDE5 inhibitors.
Frequently asked questions
How long does Cialis last? ▾
According to clinical trial data, a single on-demand dose of Cialis can support erectile response for up to 36 hours after dosing — the longest effect window of any approved PDE5 inhibitor. Onset typically begins within 30 to 60 minutes. The 36-hour figure does not mean a continuous erection: sexual stimulation is needed each time the medication produces its effect. Individual response varies, and the duration shortens at lower doses.
Cialis on-demand or daily — which is better? ▾
On-demand dosing (10mg or 20mg) is preferred when sexual activity is occasional and a planned interval before each occurrence is acceptable. Daily dosing (2.5mg or 5mg) suits men with frequent or unpredictable sexual activity, or those who also have BPH symptoms. According to the prescribing information, the choice depends on lifestyle, comorbidities and tolerability. The decision is made by the prescriber after evaluating individual circumstances.
Can Cialis be taken with food and alcohol? ▾
Cialis can be taken with or without food — absorption is not affected by meals, including high-fat meals. This is a clinical advantage compared with sildenafil. Moderate alcohol use is unlikely to alter the pharmacokinetics, but heavy intake may potentiate the blood pressure-lowering effect of tadalafil and impair erectile response independently. According to the prescribing information, alcohol consumption should be moderate during treatment.
Is Cialis the same as generic tadalafil? ▾
Cialis is the original brand of tadalafil manufactured by Eli Lilly. Authorised generic tadalafil contains the same active ingredient at the same strengths and meets the same regulatory bioequivalence requirements in markets where it is approved. Differences may include excipients, tablet shape, colour and price. According to regulators, an authorised generic should produce comparable clinical effects, though individual response can vary.
Does Cialis interact with other medications? ▾
Yes. Tadalafil has clinically important interactions, most notably with organic nitrates and guanylate cyclase stimulators (e.g. riociguat), where the combination can cause severe hypotension and is contraindicated. Other interactions include alpha-blockers, certain antifungal and HIV medications, and grapefruit juice in large quantities. According to the prescribing information, anyone taking other medicines should disclose them to a clinician before starting Cialis.
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The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.