> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hi-doctor.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Tadalafil (Cialis) for erectile dysfunction

> How tadalafil works, its 36-hour window, EU authorisation since 2002, dosing options and the side effects reported in trials.

Tadalafil is a prescription tablet for erectile dysfunction, authorised across the EU since 2002. Like other PDE5 inhibitors it relaxes the blood vessels in the penis so blood can flow in, and sexual arousal is still needed for it to work. Its distinguishing feature is how long the effect lasts — the EU product information reports a measurable effect up to 36 hours after a dose.

## What it is

<Info>
  **Active ingredient:** Tadalafil · **Dosages:** 10 / 20 mg on demand · 5 mg daily
</Info>

Tadalafil is a PDE5-inhibitor tablet taken by mouth. It is indicated for erectile dysfunction in adult men — the inability to achieve or maintain an erection sufficient for satisfactory sexual performance — and, at a daily low dose, for the signs and symptoms of benign prostatic hyperplasia (an enlarged prostate) in adult men. It also comes as a low-dose tablet taken once a day rather than before sex, and it cannot be combined with nitrate heart medicines.

## How it works

<CardGroup cols={3}>
  <Card title="Arousal releases nitric oxide" icon="bolt">
    Sexual arousal is still needed — tadalafil does not create an erection on its own.
  </Card>

  <Card title="Tadalafil blocks the PDE5 enzyme" icon="lock">
    Tadalafil is a selective, reversible blocker of phosphodiesterase type 5 (PDE5), an enzyme whose normal job is to break down cGMP. With PDE5 blocked, cGMP builds up in the erectile tissue instead of being cleared away as fast as it appears.
  </Card>

  <Card title="Blood flows in, erection follows" icon="droplet">
    Higher cGMP relaxes the smooth muscle in the arteries of the corpus cavernosum, so blood flows into the penis and an erection can form. The same relaxation happens in the prostate and bladder, which is why a daily dose can also ease urinary symptoms.
  </Card>
</CardGroup>

<CardGroup cols={2}>
  <Card title="On demand" icon="hourglass">
    One tablet at least 30 minutes before sex. Effect window up to 36 hours.
  </Card>

  <Card title="Daily option" icon="calendar-check">
    A low-dose (2.5 mg or 5 mg) tablet taken once every day rather than before sex.
  </Card>
</CardGroup>

## EU authorisation

Tadalafil (Cialis) has been authorised for use in the EU since **12 November 2002**, so a licensed doctor can prescribe it when it is clinically appropriate. Cialis is centrally authorised, so a single EU authorisation covers all 27 member states; it is held by Eli Lilly Nederland B.V. It is the only one of the EU erectile-dysfunction tablets that also carries an authorised indication for benign prostatic hyperplasia. The lower 2.5 mg and 5 mg strengths are the ones used for daily dosing rather than on-demand use.

* **EMA EPAR — Cialis (tadalafil)**, EMEA/H/C/000436, marketing authorisation issued 12/11/2002
* **EMA — Cialis EPAR product information** (SmPC sections 4.2, 4.8, 5.1)
* ***J Urol* 2002** — Efficacy and safety of tadalafil: results of integrated analyses (PMID 12352386)

## What the studies reported

The 7.9-point IIEF change reported in the pooled analysis is the within-group change from baseline rather than the difference from placebo. It pooled five 12-week manufacturer-run trials.

## What has been reported

| Effect                  | Reported frequency                                                                                                                                                |
| ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Headache                | Common (1 in 100 to 1 in 10 men, EU product information). Frequency rises with higher doses; with once-daily dosing, most headaches occur in the first 10–30 days |
| Back pain               | Common (1 in 100 to 1 in 10 men). One of the most frequently reported reactions, with frequency rising at higher doses                                            |
| Myalgia (muscle pain)   | Common (1 in 100 to 1 in 10 men), rising at higher doses                                                                                                          |
| Dyspepsia (indigestion) | Common (1 in 100 to 1 in 10 men)                                                                                                                                  |
| Flushing                | Common (1 in 100 to 1 in 10 men)                                                                                                                                  |
| Nasal congestion        | Common (1 in 100 to 1 in 10 men)                                                                                                                                  |

<Warning>
  **Non-arteritic anterior ischaemic optic neuropathy (NAION):** contraindicated in men who have lost vision in one eye because of NAION, whether or not the episode was linked to a PDE5 inhibitor.

  **Nitrates:** contraindicated with nitrate medicines and with guanylate cyclase stimulators, and after a recent heart attack (within 3 months) or stroke (within 6 months). Nitrates and poppers are contraindicated because blood pressure can fall dangerously.
</Warning>

## Who it is not suitable for

Tadalafil is not suitable for men who have lost vision in one eye due to NAION, or who take nitrate medicines or guanylate cyclase stimulators, or who have had a heart attack in the last 3 months or a stroke in the last 6 months.

## How Hi-Doctor handles it

An EU-licensed doctor reviews your case and decides which regimen fits it. **On demand:** 30–60 minutes before activity, effect window up to 36 hours. **Effect window:** up to 36 hours — a low-dose daily regimen is also available for continuous use when clinically appropriate.

The consultation fee is listed on [pricing](/essentials/pricing); the medicine itself is paid separately at a pharmacy.

## Related reading

* [Alprostadil](/library/medicines/alprostadil) — an option when oral PDE5 inhibitors don't work or aren't allowed
* [Priligy](/library/medicines/priligy) — why Hi-Doctor doesn't prescribe it, and what it offers instead
* [How a consultation works](/essentials/how-it-works)
* [Safety and eligibility](/essentials/safety)
* [Erectile dysfunction](/library/conditions/erectile-dysfunction)
* [Sildenafil (Viagra)](/library/medicines/viagra)

## Common questions

<AccordionGroup>
  <Accordion title="How does tadalafil work?">
    Tadalafil blocks the PDE5 enzyme that normally ends an erection, keeping the blood vessels in the penis relaxed so blood can flow in when a man is sexually aroused. Sexual arousal is still needed for it to work.
  </Accordion>

  <Accordion title="How long does tadalafil last?">
    The EU product information reports a measurable effect up to 36 hours after a dose. This is what sets tadalafil apart from other PDE5 inhibitors — it allows spontaneity rather than planning around a short window.
  </Accordion>

  <Accordion title="Can I take tadalafil every day?">
    Yes. A low-dose tablet (2.5 mg or 5 mg) can be taken once a day for continuous use, rather than before sex. The same daily dose can also ease urinary symptoms from an enlarged prostate.
  </Accordion>

  <Accordion title="What are the most common side effects?">
    Headache, back pain, muscle pain, indigestion, flushing and nasal congestion are all listed as common — between 1 in 100 and 1 in 10 men. Most headaches with once-daily dosing occur in the first 10 to 30 days.
  </Accordion>

  <Accordion title="Who should not take tadalafil?">
    Men who have lost vision in one eye due to NAION, who take nitrate medicines or guanylate cyclase stimulators, or who have had a heart attack in the last 3 months or a stroke in the last 6 months. Nitrates and poppers are contraindicated because blood pressure can fall dangerously.
  </Accordion>

  <Accordion title="Is tadalafil authorised in the EU?">
    Yes. Tadalafil (Cialis) has been authorised in the EU since 12 November 2002, held by Eli Lilly Nederland B.V. It is the only EU erectile-dysfunction tablet that also carries an authorised indication for benign prostatic hyperplasia.
  </Accordion>
</AccordionGroup>

## Start a consultation

<Card title="Sexual health consultation" icon="stethoscope" href="https://hi-doctor.ai/consultation/sexual-health/1">
  Answer the sexual health questionnaire and a registered doctor reviews it.
  They decide whether treatment is appropriate, which one, and at what dose —
  and declining is a normal outcome. See [what it costs](/essentials/pricing)
  and [how the review works](/essentials/how-it-works).
</Card>

<Warning>
  This page is reference information, not medical advice and not a prescription.
  Whether a medicine is appropriate for you is decided by a registered doctor
  after reviewing your consultation.
</Warning>