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How once-daily 2.5 mg Cialis compares with an as-needed 20 mg tablet

6 min readReviewed 21 August 2026. Updated

At a glance

Page typeNote
Daily lock2.5 mg
As-needed step20 mg
ReviewerCamille Rousseau, MD

CIALIS for once daily use in erectile dysfunction starts at 2.5 mg at about the same time each day. As-needed CIALIS in most patients starts at 10 mg and may increase to 20 mg, once per day.

Split card comparing daily vs on-demand tadalafil rhythm icons

01The once-daily 2.5 mg line

CIALIS for once daily use in erectile dysfunction starts at 2.5 mg, taken at approximately the same time every day. The once daily dose may be increased to 5 mg based on individual efficacy and tolerability. Once daily tadalafil is taken without regard to the timing of sexual activity.

Sexual stimulation is needed. Tadalafil may be taken with or without food. Do not split tadalafil tablets; the entire dose should be taken. Do not take a double dose of tadalafil to make up a missed dose.

Initial U.S. Approval of CIALIS is 2003. CIALIS is indicated for erectile dysfunction. Tablets are 2.5 mg, 5 mg, 10 mg, and 20 mg.

02The 5 mg once-daily prostate line

The recommended dose of tadalafil for once daily use for BPH is 5 mg, taken at approximately the same time every day. The recommended dose for once daily use for ED and BPH together is also 5 mg, taken at approximately the same time every day.

CIALIS is indicated for signs and symptoms of BPH. CIALIS is indicated for ED and BPH together. When tadalafil is started with finasteride for BPH, 5 mg daily is recommended for up to 26 weeks. The incremental benefit of tadalafil beyond 26 weeks is unknown.

Tadalafil is not recommended in combination with other alpha-blockers for the treatment of BPH. Patients on an alpha-blocker for BPH should discontinue the alpha-blocker at least one day prior to starting once daily tadalafil for BPH.

03The as-needed 10 to 20 mg line

As-needed CIALIS in most patients starts at 10 mg, taken prior to anticipated sexual activity. The dose may be increased to 20 mg or decreased to 5 mg. The maximum recommended dosing frequency is once per day.

Tadalafil for use as needed was shown to improve erectile function compared to placebo up to 36 hours following dosing.

How to cite this page - Vancouver style

Halo Medix Medicines Reference. How once-daily 2.5 mg Cialis compares with an as-needed 20 mg tablet [Internet]. Montreal: Halo Medix; 21 August 2026 [cited 2026 Aug 21]. Available from: https://halomedix.com/notes/tadalafil-daily-vs-demand/

Sources and how this page was reviewed

  1. DailyMed - CIALIS (tadalafil) tablets

Numbers come from the cited labels. Dr. Camille Rousseau, MD reads the draft, then the page is dated. See the method page and editorial standards.

Reader questions

('Readers around Montreal asked how daily 2.5 mg sits next to a 20 mg as-needed tablet. ', 'Answers follow the U.S. Cialis label.')

Isabelle Fortin, Outremont asks

Does daily ED Cialis start at 5 mg?

Reply from our reviewer

The recommended starting dose of tadalafil for once daily use in erectile dysfunction is 2.5 mg, taken at approximately the same time every day. The once daily dose may be increased to 5 mg based on individual efficacy and tolerability. Once daily tadalafil is taken without regard to the timing of sexual activity. Sexual stimulation is needed. Tadalafil may be taken with or without food. The BPH once-daily dose is 5 mg. That line is a different labelled indication from the 2.5 mg ED-daily start.

Karim Bensalem, Saint-Laurent asks

If I take 2.5 mg every morning, may I add 20 mg on Saturday?

Reply from our reviewer

Do not combine CIALIS with other PDE5 inhibitors or other ED therapies. The maximum recommended dosing frequency is once per day. As-needed use and once-daily use are written as separate regimens.5 mg once daily. The weekend note locks the 20 mg as-needed step. Do not take a double dose of tadalafil to make up a missed dose. Do not split tadalafil tablets; the entire dose should be taken.

Claire Lefebvre, Verdun asks

What dose is written for BPH alone?

Reply from our reviewer

The recommended dose of tadalafil for once daily use for BPH is 5 mg, taken at approximately the same time every day. The recommended dose for once daily use for ED and BPH together is also 5 mg. When tadalafil is started with finasteride for BPH, 5 mg daily is recommended for up to 26 weeks. The incremental benefit of tadalafil beyond 26 weeks is unknown. Tadalafil is not recommended in combination with other alpha-blockers for the treatment of BPH. Patients on an alpha-blocker for BPH should discontinue the alpha-blocker at least one day prior to starting once daily tadalafil for BPH.

Denis Paquette, Hochelaga asks

How long is the half-life on the daily tablet?

Reply from our reviewer

The mean terminal half-life is 17.5 hours in healthy subjects. After a dose, the maximum tadalafil concentration is reached between 30 minutes and 6 hours. The median time to maximum concentration is about 2 hours. In trials of CIALIS for once daily use, a total of 1434, 905, and 115 were treated for at least 6 months, 1 year, and 2 years, respectively. At a dose of 5 mg, the incidence and severity of back pain was not significantly different than in the general population in the cited pharmacology text.

Lucie Bergeron, Pointe-Claire asks

Does food change the once-daily 2.5 mg swallow?

Reply from our reviewer

CIALIS may be taken without regard to food. Rate and extent of tadalafil absorption are not influenced by food. Once daily tadalafil is taken without regard to the timing of sexual activity. The recommended starting dose of tadalafil for once daily use in erectile dysfunction is 2.5 mg, taken at approximately the same time every day. The once daily dose may be increased to 5 mg based on individual efficacy and tolerability. Sexual stimulation is needed. Do not split tadalafil tablets; the entire dose should be taken. Store at 25 C (77 F); excursions permitted to 15 to 30 C (59 to 86 F).

Yanis Haddad, Montréal-Nord asks

What did the 12-week once-daily ED trials report at 2.5 mg?

Reply from our reviewer

In three placebo-controlled clinical trials of 12 weeks duration for once-daily ED, headache occurred in 3% at 2.5 mg, 6% at 5 mg, and 5% on placebo. Dyspepsia occurred in 4% at 2.5 mg, 5% at 5 mg, and 2% on placebo. Back pain occurred in 3% at 2.5 mg, 3% at 5 mg, and 1% on placebo. Myalgia occurred in 2% at 2.5 mg, 2% at 5 mg, and 1% on placebo. Nasal congestion occurred in 2% at 2.5 mg, 2% at 5 mg, and 0% on placebo. Flushing occurred in 1% at 2.5 mg, 3% at 5 mg, and 1% on placebo. In trials of CIALIS for once daily use, a total of 1434, 905, and 115 were treated for at least 6 months, 1 year, and 2 years, respectively.

Émilie Roy, Saint-Lambert asks

How is a missed once-daily 2.5 mg tablet handled?

Reply from our reviewer

If you miss a dose, you may take it when you remember but do not take more than one dose per day. Do not take a double dose of tadalafil to make up a missed dose. CIALIS for once daily use in erectile dysfunction starts at 2.5 mg, taken at approximately the same time every day. The mean terminal half-life is 17.5 hours in healthy subjects. Keep out of reach of children.