Maximum Tadalafil Dose: UK Limits and Safety

The maximum licensed dose of tadalafil depends on how it is being taken.

For on-demand use in the UK, the ceiling is 20mg, taken as a single tablet no more than once in any 24-hour period. For once-daily use, the maximum is 5mg, taken every day.

These are two separate limits for two different ways of using the same medicine, not one number that applies to everyone. They should not be combined or exceeded.

This guide sets out the licensed limits for tadalafil tablets, the factors that can lower what is safe for you, including kidney and liver function, what can happen if you take more than recommended, and when to speak to a prescriber.

That matters because taking more tadalafil does not make it work better. It increases the risk of side effects, and may mean your treatment needs reviewing rather than raising.

What Is the Maximum Dose?

It is 20mg for on-demand use, or 5mg for once-daily use. These figures cannot be added together, or exceeded on the assumption that more will work better.

On-Demand Maximum: 20mg

For on-demand treatment of erectile dysfunction, tadalafil usually starts at 10mg, taken at least 30 minutes before anticipated sexual activity. Its effects can last up to 36 hours after a single dose.

Depending on your response and tolerability, a prescriber may increase this to 20mg, which is the licensed maximum for this pattern of use.

It should never be taken more than once in any 24-hour period, whatever the dose.

Once-Daily Maximum: 5mg

For daily tadalafil, the standard dose is 5mg, taken at approximately the same time every day, with or without food.

That is also the maximum for this pattern of use. It is not increased. If 5mg is not well tolerated, a prescriber may reduce it to 2.5mg instead.

The Maximum Per Day

Tadalafil should not be taken more than once in any 24-hour period.

For on-demand dosing, that means one tablet, at up to 20mg, in any given day.

For once-daily dosing, the daily dose is the maintenance dose itself, 5mg or 2.5mg, taken once and not repeated or topped up later in the day.

The two patterns are not meant to be combined. Someone on once-daily 5mg should not also take on-demand tablets on top without a prescriber's specific guidance, since that would exceed what has been assessed as safe for them.

Why Tadalafil Has Two Different Maximums

Both patterns are licensed treatments for erectile dysfunction. The choice between them depends on how often treatment is likely to be needed, not on which one is stronger.

The two maximums exist because the patterns work differently, not because one is simply a bigger dose of the other.

On-demand dosing relies on a single, larger tablet to produce an effect for that occasion, which is why its maximum of 20mg is higher.

Once-daily dosing maintains a small, steady level of the medicine in the body, so a much smaller dose of up to 5mg is enough to support erectile function when there is sexual stimulation. The 20mg on-demand dose is not intended for continuous daily treatment.

How a Prescriber Decides Your Starting Dose

Reaching the maximum is not the default expectation, and most people do not start there.

For on-demand treatment, the recommended starting dose is 10mg, with 20mg reserved for those who need it and tolerate it well. For once-daily treatment, it is 5mg, which may be reduced to 2.5mg depending on tolerability.

The right dose depends on your response, tolerability, kidney and liver function and other medicines, all assessed during your clinical review rather than assumed upfront.

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Why the Maximum Is Not the Same for Everyone

The 20mg and 5mg figures are the standard licensed maximums for adults with typical kidney and liver function. For some people, the safe maximum is lower.

Kidney Function

In severe kidney impairment, the maximum recommended on-demand dose is 10mg, and once-daily tadalafil is not recommended. Tadalafil exposure increases when kidney function is significantly reduced, so dosing needs careful assessment by a prescriber.

Liver Function

In mild to moderate liver impairment, the on-demand dose should not exceed 10mg, because clinical data at higher doses are limited. Once-daily treatment, and use in severe liver impairment, should only be considered after an individual assessment of benefits and risks.

Other Medicines

Some medicines raise tadalafil levels in the body, so a lower dose may be needed even though the tablet strength is the same. That is why your prescriber needs a full list of everything you take.

What Happens If You Take More Than the Maximum?

Taking more than the licensed maximum does not reliably make tadalafil work better, and it increases the risk of side effects. Its effect on blood pressure becomes more pronounced at higher exposure.

Effects more likely at higher-than-intended levels include:

• A more noticeable headache, or dizziness
• More pronounced flushing
• A greater drop in blood pressure, particularly alongside other blood-pressure-lowering medicines
• A higher risk of a prolonged erection, which needs urgent medical attention

If you have taken too much and feel unwell, seek medical attention promptly.

Is a Higher Dose More Effective?

Response does vary between the licensed doses, which is why tadalafil comes in more than one strength and why a prescriber may adjust it within that range.

That is a different thing entirely from exceeding the maximum. Going beyond 20mg on demand or 5mg daily is not a bigger version of the same adjustment. It is outside what has been tested and licensed as safe, and no legitimate provider will support it.

If Your Current Dose Does Not Seem to Be Working

It is common to expect too much too soon, or to assume a lack of results means the dose needs to go up. Before concluding that, consider a few other factors.

Stimulation. Tadalafil works by increasing blood flow, not by causing an automatic erection. Sexual stimulation is still required.

Timing. For on-demand use, taking the tablet at least 30 minutes beforehand matters. For once-daily use, it takes around five days of consistent dosing to reach a steady level, so judging it too early can mislead.

Alcohol. Drinking heavily can make treatment less effective.

If none of that explains it, the right next step is a review with a prescriber, not a higher dose taken on your own initiative. A review can look at whether the current approach is right for you, whether something else is contributing, or whether a different licensed option would suit you better.

Missed Doses

For daily tadalafil, if you miss a dose, take it as soon as you remember on the same day, or skip it if it is almost time for the next one. Never take two doses together to make up for a missed one.

For on-demand tadalafil, there is no schedule to miss. But if a tablet does not seem to have worked, do not take a second one the same day. Wait, and discuss it with a prescriber.

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Who Should Not Take Tadalafil at Any Dose

Nitrates: An Absolute No

Tadalafil must never be taken by anyone using a nitrate medicine, in any form, including nitrates for chest pain and recreational nitrite products. The combination can cause a dangerous drop in blood pressure, and that applies whether the dose is 2.5mg or 20mg.

Because tadalafil's effect on blood pressure lasts some time after the last dose, anyone needing emergency nitrate treatment should make sure the treating clinician knows they have taken tadalafil recently, and roughly how much.

Other Interactions

Tell your prescriber about all the medicines you take, particularly:

• Alpha blockers, a type of blood pressure medicine, since combining them with tadalafil increases the risk of low blood pressure
• Other erectile dysfunction treatments, which should not be combined with tadalafil unless a prescriber specifically advises it
• Medicines affecting liver enzymes, which can raise tadalafil levels and effectively lower your safe maximum
• Grapefruit juice, which may increase tadalafil exposure, so mention it if you drink it regularly

Medical Disclaimer

This article is for general information only and is not a substitute for professional medical advice. Tadalafil is a prescription medicine, and the maximum safe dose varies between individuals depending on their health and other medicines, particularly for people with kidney disease, cardiovascular disease or high blood pressure. Never take more than your prescribed dose.

If you experience chest pain, a sudden change in vision or hearing, an erection lasting longer than four hours, or any other symptom that concerns you, seek urgent medical attention or call 999.

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