Tadalafil dosage: A complete guide
- A complete overview of available doses
- Daily vs on-demand dosing: How they differ and who each suits
- The mechanism behind the 36-hour window for Tadalafil 20 mg
- Why 20 mg is the maximum dose for ED and what happens beyond it
- Dosing for BPH: How the schedule differs from ED prescribing
- Factors that affect dose choice
- What to do if your dose is not working
- Tadalafil dosage options: An overview
- Tadalafil 5 mg daily: Who it is for and what to expect?
- Tadalafil 10 mg and 20 mg on demand: What to know
- How long does tadalafil 20 mg last?
- Maximum dose: Why 20 mg is the ceiling for ED
- Tadalafil dosage for BPH vs. Erectile dysfunction
- Factors affecting dose choice
- What to do if your dose is not working
- Final thoughts
Tadalafil dosage options: An overview
Tadalafil is available in four dose strengths in the UK, used across two distinct dosing regimens. The table below summarises the key details for each.
| Dose | Regimen | Indication | Timing | Max frequency |
|---|---|---|---|---|
| 2.5 mg | Daily | ED | Same time each day | Once daily |
| 5 mg | Daily | ED and/or BPH | Same time each day | Once daily |
| 10 mg | On demand | ED | 30 min to 2 hours before activity | Once in 24 hours |
| 10 mg | On demand | ED | 30 min to 2 hours before activity | Once in 24 hours |
Source: Tadalafil Summary of Product Characteristics
The choice between daily and on-demand dosing is not purely a clinical decision; it also reflects lifestyle preferences and how frequently you anticipate needing the medicine. Both regimens are equally licensed and clinically effective, and the right choice is worth discussing with your prescriber.
Tadalafil 5 mg daily: Who it is for and what to expect?
Unlike other ED medicines, tadalafil is the only PDE5 inhibitor with a licensed daily low-dose regimen. This makes it a meaningfully different option in practice, particularly for men who want to remove the need to plan around taking a tablet altogether.
Taking Tadalafil 5 mg once daily maintains a consistent, steady level of the drug in the bloodstream. This means the medicine is continuously present and active, so there is no need to plan around dosing, and no timing window to manage.
The daily regimen is also licensed for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH), making 5 mg daily a practical option for men managing both ED and BPH with a single tablet. We will discuss this in more detail later.
Who is daily Tadalafil right for?
Daily tadalafil at 2.5 mg or 5 mg tends to suit men who:
- Have sex frequently and find on-demand dosing inconvenient
- Value spontaneity and prefer not to plan around taking a tablet
- Experience bothersome side effects from the higher on-demand doses, and find the lower steady-state level is typically better tolerated
- Are managing both ED and BPH simultaneously
How to take daily Tadalafil
Take one tablet at the same time each day, with or without food. Consistency of timing helps maintain stable blood levels. It takes approximately five days of daily dosing to reach steady-state blood levels, so the full benefit may not be apparent in the first few days.
Important!
If you miss a daily dose, take it as soon as you remember, unless it is almost time for your next dose, in which case skip the missed one and resume your normal schedule. Do not take two doses on the same day to make up for a missed one.
Tadalafil 10 mg and 20 mg on demand: What to know
On-demand Tadalafil is taken when needed, before anticipated sexual activity. It produces a more pronounced peak blood level than daily dosing, which is why it is associated with a slightly higher incidence of side effects.
Tadalafil 10 mg
10 mg is the standard starting dose for on-demand tadalafil. It is taken approximately 30 minutes to two hours before sexual activity and should not be taken more than once in any 24-hour period.
For most men, 10 mg provides a satisfactory balance of effectiveness and tolerability. If 10 mg produces a sufficient response with acceptable side effects, there is no clinical reason to increase the dose.
Tadalafil 20 mg
20 mg is the maximum on-demand dose and is appropriate where 10 mg has not produced a sufficient response. As with 10 mg, it is taken 30 minutes to two hours before sexual activity, no more than once in 24 hours.
The higher dose produces a stronger peak blood level, which correlates with greater efficacy for some men but also with a higher incidence of side effects. A prescriber should review your response to 10 mg before a dose increase to 20 mg is considered.
Important!
Do not increase your dose from 10 mg to 20 mg without speaking to your prescriber first. If 10 mg has not been effective, a prescriber can assess whether a higher dose is appropriate, or whether a different approach, such as daily dosing or a different medicine, may be more suitable.
How long does tadalafil 20 mg last?
Tadalafil has a half-life of approximately 17.5 hours, roughly four times longer than Sildenafil or Vardenafil. This means that after a single 20 mg dose, Tadalafil blood levels remain at clinically meaningful concentrations for up to 36 hours, supporting the ability to achieve an erection in response to arousal throughout that window.
The same 36-hour duration applies to the 10 mg dose. The difference between 10 mg and 20 mg is not the length of the window but the peak blood level within it, which influences how reliably the erection response is supported.
Good to know
The 36-hour duration does not mean a continuous erection for that period. It means that the physiological support for an erection in response to sexual stimulation remains present for up to 36 hours after the dose. Sexual stimulation is still required for tadalafil to produce its intended effect.
Maximum dose: Why 20 mg is the ceiling for ED
The maximum approved dose of Tadalafil for erectile dysfunction is 20 mg once in any 24-hour period. This applies regardless of whether the on-demand dose is taken as a one-off or more regularly.
Taking more than 20 mg does not produce greater efficacy for ED and significantly increases the risk of side effects, including more pronounced blood pressure reduction, headache, flushing, and back pain. The 20 mg ceiling is set based on the benefit-risk balance established in clinical trials.
It is worth noting that Tadalafil is used at higher doses (typically 40 mg once daily) for pulmonary arterial hypertension, but this is a completely different indication managed by specialists, with a different benefit-risk profile and clinical monitoring framework. This higher dose is not relevant to or appropriate for ED prescribing.
Important!
Never take more than 20 mg of Tadalafil for erectile dysfunction in any 24-hour period. If 20 mg on demand is not producing a satisfactory response, the appropriate next step is a conversation with your prescriber, not a higher dose.
Tadalafil dosage for BPH vs. Erectile dysfunction
The dosing schedule for Tadalafil differs depending on whether it is being used for ED alone, BPH alone, or both conditions simultaneously.
| Indication | Dose | Regimen |
|---|---|---|
| ED (on demand) | 10 mg or 20 mg | As needed, once in 24 hours |
| ED (daily) | 2.5 mg or 5 mg | Once daily, same time each day |
| BPH (lower urinary tract symptoms) | 5 mg | Once daily, same time each day |
| ED and BPH combined | 5 mg | Once daily, same time each day |
For men being treated for BPH alone, without ED, the licensed dose is 5 mg once daily. For men with both ED and BPH, 5 mg once daily also applies, making it a practical single-tablet option for both conditions.
On-demand dosing is not licensed or recommended for BPH. The continuous daily regimen is necessary to produce the sustained reduction in smooth muscle tone in the prostate and bladder neck that improves urinary symptoms.
Factors affecting dose choice
Several individual factors influence which dose is most appropriate and how the body responds to tadalafil.
Age
Dose adjustments are not routinely required for older men based on age alone. However, the SmPC notes that older men should be assessed carefully before a maximum 20 mg on-demand dose is prescribed, as Tadalafil clearance may be slower and tolerability to higher doses more variable.
Kidney impairment
For men with mild to moderate kidney impairment, dose adjustment is not routinely required for on-demand dosing, though the maximum dose should be applied with caution. For severe kidney impairment, on-demand Tadalafil should be used with caution and the lowest effective dose is preferred. Daily tadalafil is not recommended in men with severe kidney impairment.
Liver impairment
For men with mild to moderate liver impairment, a starting dose of 10 mg on demand is recommended, with caution around escalation to 20 mg. Tadalafil is not recommended in men with severe liver impairment.
Other medicines
Several medicines can significantly increase Tadalafil blood levels by inhibiting its metabolism, including certain antifungals (ketoconazole, itraconazole), HIV medicines (ritonavir), and the antibiotic clarithromycin. Where these are prescribed concurrently, a lower Tadalafil dose may be required. Your prescriber will take your full medication list into account before recommending a dose.
Important!
Always disclose all current medicines, including over-the-counter preparations and supplements, to your prescriber before starting tadalafil. Some interactions significantly affect blood levels and may require dose adjustment.
What to do if your dose is not working
If Tadalafil does not appear to be producing the desired effect, the first step is to review practical factors before concluding the dose is insufficient.
Consider whether:
- Sufficient time was allowed between taking the tablet and sexual activity (at least 30 minutes, ideally one hour for on-demand doses)
- The dose was taken after a very heavy meal, which can delay absorption
- Sufficient sexual stimulation was present (tadalafil requires arousal to work)
- Alcohol consumption may have been a contributing factor
If Tadalafil consistently fails to produce a satisfactory response after several attempts under appropriate conditions, speak to your prescriber. The options available include:
- Increasing the on-demand dose from 10 mg to 20 mg
- Switching from on-demand to daily dosing, which some men find more effective due to the consistent blood level
- Reviewing whether an underlying health condition or medication interaction is affecting response
- Considering an alternative PDE5 inhibitor, as individual response within the class varies
Important!
Do not self-escalate beyond the 20 mg maximum dose. If 20 mg on demand is not working, this requires clinical review rather than a higher dose.
Final thoughts
Tadalafil's flexible dosing options, from a 10 mg or 20 mg on-demand tablet to a daily 5 mg option that removes timing considerations entirely, are one of its most clinically valuable features. Getting the right dose for your individual circumstances, health status, and lifestyle is what makes treatment both effective and well tolerated.
If your current dose is not working as expected, or if you are unsure which approach is right for you, a conversation with a UK-registered prescriber is always the appropriate next step rather than adjusting your dose independently.
FAQ
What is the standard starting dose of Tadalafil?
For on-demand use, the standard starting dose is 10 mg, taken 30 minutes to two hours before sexual activity. For daily use, the starting dose is 2.5 mg, which may be increased to 5 mg based on response and tolerability.
How long does Tadalafil 20 mg last?
Up to 36 hours. Tadalafil's half-life of approximately 17.5 hours means it remains at clinically active levels for significantly longer than Sildenafil or Vardenafil. This does not mean a continuous erection; sexual stimulation is still required.
Can I take Tadalafil 20 mg every day?
On-demand Tadalafil at 10 mg or 20 mg should not be taken more than once in any 24-hour period. It is not designed for daily continuous use at these doses. If you would benefit from a daily approach, daily 2.5 mg or 5 mg is the appropriate licensed option.
What is the maximum dose of Tadalafil for ED?
20 mg once in any 24-hour period. This is the ceiling approved by the MHRA for erectile dysfunction. Higher doses do not improve efficacy for ED and significantly increase the risk of side effects.
Is Tadalafil 5 mg enough for ED?
For many men on the daily regimen, 5 mg is entirely sufficient. The lower continuous blood level supports erectile function effectively for the majority of men who use this approach. If 5 mg daily is not producing a satisfactory response, a prescriber can review whether 10 mg or 20 mg on demand may be more appropriate.
How long before sex should I take Tadalafil?
At least 30 minutes before sexual activity, though one hour is generally recommended for the most reliable onset. For daily dosing, timing relative to sexual activity is not relevant, as the medicine is present continuously.
Does Tadalafil dose need to be adjusted for older men?
Routine dose adjustment based on age alone is not required, but the prescriber should consider individual tolerability carefully before prescribing the maximum 20 mg on-demand dose in older men.
The DoktorABC medical advisory board
Dr. Roland Ruiken
Medical advisor, Norway
Dr. Viktor Simunovic
Medical advisor, Croatia