Four Licensed ED Tablets in the UK Compared

Comparing the Four Licensed Erectile Dysfunction Tablets in the UK

Sildenafil, tadalafil, vardenafil and avanafil all belong to the same class, PDE5 inhibitors, and all treat erectile dysfunction. They share important similarities, but their product information differs on timing, food effects and side effects, and those differences can matter when a prescriber chooses between them.

This page sets them side by side using figures from each medicine's own UK product information. No figure is carried across from one medicine to another, which sounds obvious but is the most common mistake in comparisons like this.

Key things to know

All four are PDE5 inhibitors. Vardenafil and avanafil are prescription-only, while sildenafil and tadalafil each have one pharmacy-medicine product alongside their prescription versions
All four must never be taken with nitrates or nitric oxide donors. That rule does not vary
The documented onset figures are close: avanafil at around 15 minutes in one study, tadalafil as early as 16 minutes, and sildenafil at a median of 25 minutes when taken fasting
Tadalafil is the only one whose absorption is not affected by food
Tadalafil is the only one with a recorded effectiveness window, up to 36 hours. The others are described by half-life, which measures something different
Treatment suitability depends on an individual clinical assessment, which no comparison table can replace

What All Four Have in Common

All four block an enzyme called PDE5, which normally breaks down a messenger called cGMP. Leaving more cGMP in place lets the smooth muscle in blood vessel walls relax, so the vessels supplying the penis fill more readily during sexual stimulation. None of them works without stimulation.

Because they act on the same pathway, their side effects overlap considerably. Headache, flushing and nasal congestion are reported with more than one of them.

The Four Compared

Every figure below comes from UK product information for that specific medicine.

Feature	Sildenafil	Tadalafil	Vardenafil	Avanafil
Documented timing	Median onset 25 minutes, fasting	Effective from as early as 16 minutes	Peak blood level at 30 to 120 minutes, median 60	Effective at around 15 minutes in one study
Usual timing beforehand	About an hour	At least 30 minutes	25 to 60 minutes	15 to 30 minutes
Duration measure recorded	Effect continuing 4 to 5 hours	Effectiveness maintained up to 36 hours	Half-life about 4 to 5 hours	Half-life about 6 to 17 hours
Half-life	3 to 5 hours	17.5 hours on average	4 to 5 hours	6 to 17 hours
Effect of food	Peak delayed by 60 minutes, and reduced by 29%	Not affected by food	A very high-fat meal slows absorption, but total amount unchanged	Onset may be delayed
Very common side effects	Headache	None recorded	Headache	None recorded
Common side effects	Dizziness, flushing, nasal congestion, nausea, indigestion, visual colour changes, blurred vision	Headache, indigestion, flushing, back pain, muscle pain, nasal congestion	Flushing, dizziness, nasal congestion, indigestion	Headache, flushing, nasal congestion, back pain, dizziness, sinus congestion
Nitrate contraindication	Applies	Applies	Applies	Applies
Form that dissolves in the mouth	50mg orodispersible film	None	10mg orodispersible tablet	None

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Onset: How Quickly Each One Works

Avanafil showed effectiveness at around 15 minutes in one study, tadalafil from as early as 16 minutes, and sildenafil at a median of 25 minutes when taken fasting. For vardenafil, the product information records peak blood levels at 30 to 120 minutes, and a usual timing of 25 to 60 minutes beforehand.

Why These Figures Cannot Settle Which Is Fastest

The numbers come from four separate development programmes, with different study designs, endpoints and definitions of onset, and none compared the four directly. A figure of 15 minutes from one programme and 16 from another does not show that one acts faster, because they were never measured the same way.

There is a second reason to hold any ranking loosely. Onset in a study population is not onset in you, and food shifts it for three of the four.

Onset Is Not the Same as Peak

These are different events, and they are often confused. Tadalafil reaches its peak blood level at about 2 hours, but shows effectiveness from 16 minutes. Avanafil peaks within 30 to 45 minutes when taken fasting. None of them waits for the peak to start working.

Duration: Why the Figures Need Care

This is the most misunderstood part of any comparison, and the error is in the measurement rather than the numbers.

Tadalafil's product information records effectiveness maintained up to 36 hours, which is an effectiveness window established in a study. Sildenafil's records an effect continuing 4 to 5 hours, alongside a half-life of 3 to 5 hours. Vardenafil records a half-life of about 4 to 5 hours, and avanafil a half-life of about 6 to 17 hours.

Half-life is the time it takes for the amount in the body to fall by half. It measures how the body clears a medicine, not how long it works. Setting a 36-hour window against a 4-to-5-hour half-life, and concluding that one lasts seven times longer, compares two different quantities.

What 36 Hours Describes

It describes a window within which tadalafil still worked. It does not describe a continuous effect for a day and a half.

In practice, it means tadalafil removes the need to time a tablet closely to an occasion. That is a real difference from the other three, and the reason it suits some people and not others. It is not a claim that its effect is stronger. Tadalafil also has a licensed daily option for people who need treatment regularly.

Avanafil's Wide Half-Life Range

Avanafil's half-life is reported as a range of about 6 to 17 hours. These values vary between individuals and study conditions, so the range does not predict what will happen for any one person.

Food: An Important Difference

If one difference matters most for day-to-day use, it is this.

Tadalafil is not affected by food, and can be taken with or without a meal.

Sildenafil is affected. Taken with food, its peak is delayed by an average of 60 minutes, and reduced by 29%.

Vardenafil is affected by a very heavy meal specifically. A meal containing 57% fat slows absorption, though the total amount absorbed is unchanged, and a meal containing 30% fat makes no difference.

Avanafil may take longer to start working if taken with food.

Side Effects: Where the Profiles Differ

Most of the side effects are shared, because the mechanism is shared, but a few differences stand out.

Visual Effects Are a Sildenafil Feature

Sildenafil is the only one of the four whose common side effects include visual colour changes and blurred vision. They do not appear in the common lists for the other three. Anyone who has had visual disturbance on sildenafil has a specific, documented reason to raise it at review.

Back and Muscle Pain Are Tadalafil and Avanafil Features

Back pain appears in the common side effects for tadalafil and avanafil, and muscle pain for tadalafil. Neither appears in the common lists for sildenafil or vardenafil.

Dizziness Differs

Dizziness is common with sildenafil, vardenafil and avanafil, but uncommon with tadalafil, meaning at least 1 in 1,000 but fewer than 1 in 100 people.

A Specific Vardenafil Caution

Vardenafil carries a caution about heart rhythm, known as the QT interval, in people with certain heart conditions or taking certain medicines.

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Planned Use and Unplanned Situations

This is the practical question beneath most comparisons, and the answer follows from the timing and food figures rather than preference.

Tadalafil's food-independent absorption and longer window may suit people who would rather not time treatment closely around sexual activity. The shorter-acting options may suit people who prefer a defined window around a particular occasion. Neither approach is better. They suit different circumstances, and your prescriber will decide what is right for you.

If One Does Not Work

If a medicine does not seem to work, review how it was taken, and whether anything else affected the result, before considering a change.

Switching is a normal clinical step, and it is a prescriber's decision. Bring specific information: which medicine, what happened, how long beforehand you took it, whether you had eaten, whether alcohol was involved, and how many occasions you are describing. That turns a switch into a reasoned change rather than a guess.

Do not take a higher dose, or combine PDE5 inhibitors, to make up for a disappointing result unless a prescriber specifically tells you to.

How a Prescriber Chooses

Your medicines. Nitrates and nicorandil rule out all four. An alpha blocker, particularly doxazosin, changes the picture
Your heart health and blood pressure. Uncontrolled high blood pressure and low blood pressure are contraindications in their own right
Kidney and liver function, which can affect the choice or dose
Whether use is likely to be planned or unpredictable, which is where timing and food differences matter
What you have tried before, and what happened, which is often the most useful single piece of information
Other conditions, and any relevant surgery

None of those is visible in a comparison table, which is why the table cannot make the decision.

What This Comparison Cannot Tell You

The onset figures come from four separate programmes with different designs, so they do not establish a ranking
Duration is recorded differently across the four, so tadalafil's 36-hour figure and the others' half-lives are not directly comparable
No product information establishes that any one is more effective than another in the general population
Nothing here predicts an individual response. Results vary between individuals

Safety

All four are used to treat erectile dysfunction. None may be taken with nitrate medicines, because the combination can cause a dangerous fall in blood pressure.

Seek urgent medical attention for chest pain, sudden changes in vision or hearing, or an erection lasting four hours or longer.

Medical Disclaimer

This page provides general information comparing the four licensed erectile dysfunction tablets in the UK. It does not provide personalised prescribing or dosing instructions. Treatment suitability depends on an individual clinical assessment, and individual response varies.

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Frequently Asked Questions

What are the four licensed erectile dysfunction tablets in the UK?

Sildenafil, tadalafil, vardenafil and avanafil. All four are phosphodiesterase type 5 inhibitors, and all four are contraindicated with nitrates, nitric oxide donors and riociguat. Most products are prescription only, although sildenafil 50mg and tadalafil 10mg are also available as pharmacy medicines following a pharmacist assessment.

Which one acts fastest?

The reported timing figures are relatively close for some of the medicines, but they come from different studies and are not directly comparable. Avanafil demonstrated efficacy at approximately 15 minutes in one study, tadalafil as early as 16 minutes, and sildenafil had a median onset of 25 minutes in fasted patients. These figures should not be used to rank the medicines by speed.

Which one lasts longest?

Tadalafil has an efficacy window recorded as lasting up to 36 hours. For sildenafil, vardenafil and avanafil, the product information gives half-life figures rather than an equivalent efficacy-window measurement. Because these are different measures, they should not be used to produce a simple ranking of duration.

Tadalafil vs sildenafil: what is the actual difference?

The two clearest documented differences are food and timing. Tadalafil absorption is not influenced by food and efficacy was maintained up to 36 hours. Sildenafil taken with food has peak concentration delayed by 60 minutes and reduced by 29 per cent, with effectiveness continuing 4 to 5 hours.

How does vardenafil compare with tadalafil?

Vardenafil is usually taken approximately 25 to 60 minutes beforehand, with a half-life of approximately 4 to 5 hours, and a high fat meal reduces its rate of absorption. Tadalafil is unaffected by food and has a 36 hour efficacy window recorded. Headache is the most frequently reported effect for vardenafil, occurring in at least one in ten.

How does avanafil compare with tadalafil?

Avanafil is usually taken approximately 15 to 30 minutes beforehand and its onset may be delayed by food. Tadalafil is unaffected by food. Both record headache, flushing and nasal congestion as common. Tadalafil also lists back pain and muscle pain as common, whereas the avanafil leaflet records back pain as uncommon. Both record dizziness as uncommon.

Does food affect all four?

No. Tadalafil is the exception. Product information states its rate and extent of absorption are not influenced by food. The other three are affected to differing degrees, which is why generic advice about heavy meals is often wrong.

Do the side effects differ between them?

The common adverse-reaction profiles overlap considerably, but some differences appear in the product information. Sildenafil's common list includes visual colour distortions, visual disturbance and blurred vision, while back pain and muscle pain appear in the common list for tadalafil but are recorded as uncommon or rare for avanafil.

Which one is best?

That question cannot be answered in general, and no licensed information establishes one as more effective than another in the general population. The appropriate choice depends on your medicines list, blood pressure, cardiovascular history, organ function and how predictable your need is. Treatment suitability depends on an individual clinical assessment.

Which suits unplanned situations rather than planned ones?

A medicine unaffected by food with a long recorded efficacy window removes the need to time a tablet closely, which is the practical appeal of tadalafil. A shorter acting medicine with a food effect fits a planned occasion. Neither is superior, and the choice is a prescriber decision.

Can I try a different one if the first does not work?

If the first medicine does not seem to work, speak with the prescriber before changing the dose or treatment. They may review how and when it was taken, other medicines or substances that could affect the response, and whether another treatment would be appropriate. Do not combine PDE5 inhibitors.

Is there a non tablet option among these four?

A licensed sildenafil orodispersible film at 50mg is available in the UK, taken on the tongue without water. No licensed non tablet format was identified for tadalafil, vardenafil or avanafil in the product information reviewed.