Tadalafil daily or on demand: which dosing suits which man

This page is medicine information rather than an advert. Tadalafil is a prescription only medicine in the UK at every strength except the pharmacy product Cialis Together. Which dose and schedule is appropriate is a decision for a prescriber after an assessment.

Two schedules, one medicine

On demand. Usually 10 mg taken before anticipated sexual activity, adjustable between 5 mg and 20 mg depending on response and tolerance, and no more than once a day ^[1]. The useful window runs up to about 36 hours, which is the practical difference from sildenafil — you are not timing a dose against a specific hour.

Once daily. 5 mg taken at roughly the same time each day, reducible to 2.5 mg if 5 mg is not well tolerated ^[1]. Levels stay steady, so there is nothing to plan around at all.

The product information frames the choice around frequency: daily dosing is considered appropriate for men who anticipate at least two sexual attempts a week ^[1]. Below that, taking a tablet every day to cover occasional use is more medicine than the situation needs.

The honest position on which works better

Daily dosing is often marketed as superior. The evidence does not really say that. What it offers is spontaneity — no planning, no association between taking a tablet and what happens next — and steady plasma levels. Some men find that psychologically important, particularly where anxiety about performance is part of the picture, as our guide to performance anxiety and erections discusses.

What daily dosing does not do is make the medicine work in men for whom it does not work. If on-demand tadalafil at the maximum tolerated dose, taken correctly, over several separate attempts, has produced nothing, switching to daily is unlikely to be the answer — and the reason for non-response deserves looking at instead.

The prostate indication

This is the part most commonly misstated. Tadalafil is licensed in the UK for two things: erectile dysfunction, and the signs and symptoms of benign prostatic hyperplasia ^[1]. For BPH the dose is 5 mg once daily, and only 5 mg — the product information states plainly that efficacy of 2.5 mg for BPH has not been demonstrated, and that men who cannot tolerate 5 mg should move to an alternative therapy ^[1].

For a man with both an enlarged prostate causing urinary symptoms and erectile difficulty, 5 mg once daily treats both, which is a genuinely useful piece of prescribing. NICE guidance on lower urinary tract symptoms in men includes a PDE5 inhibitor recommendation for this group ^[3].

It is worth being clear about what this does not mean. Tadalafil does not shrink the prostate the way finasteride or dutasteride do, and it does not treat prostate cancer or replace assessment of urinary symptoms.

The alpha blocker question

Alpha blockers are used for high blood pressure and for prostate symptoms, so the overlap with tadalafil is common.

The product information singles out doxazosin: tadalafil increases its blood-pressure-lowering effect significantly, the effect lasts at least 12 hours, and it may be symptomatic including fainting. This combination is not recommended ^[1].

Other alpha blockers — tamsulosin, alfuzosin — are not prohibited but need care: stabilise on the alpha blocker first, start tadalafil at the lowest dose, titrate gradually, and take particular care in older men. If you take anything for your prostate or blood pressure, say so specifically rather than assuming the prescriber will infer it.

The rest of the safety picture

The absolute contraindications are the same as for any PDE5 inhibitor: nitrates in any form, nicorandil, amyl nitrite and riociguat must never be combined with it. Recent heart attack or stroke, severe heart failure, very low blood pressure and previous NAION are also contraindications.

Tadalafil’s side effect profile skews slightly differently from sildenafil’s. Headache and indigestion are common to both; tadalafil produces back pain and muscle aches more often, typically appearing 12 to 24 hours after a dose and settling within two days, and fewer visual effects. Our guide to sildenafil side effects covers the shared ground, and sildenafil vs tadalafil sets the two side by side.

One further practical note: unlike sildenafil, tadalafil absorption is not significantly affected by food, so a meal before does not have to be planned around.

A prescribing change worth knowing

Since October 2025, generically written NHS prescriptions for tadalafil and vardenafil no longer require the SLS endorsement that used to restrict them; branded Cialis and Levitra still do. In practice this makes NHS supply of generic tadalafil more straightforward than it was, which is worth knowing before assuming private supply is the only route.

Getting it right

Whichever schedule you use, the same four things determine whether a PDE5 inhibitor works: the dose, the timing, adequate sexual stimulation, and enough separate attempts to judge fairly. Our guide to how ED treatments compare covers what comes next if it genuinely does not.

This article is for general information and isn’t a substitute for advice from your own clinician. If you feel unwell, contact your GP or NHS 111. In an emergency, call 999.