Tadalafil is a medicine widely used for erectile dysfunction (ED). It belongs to the same general group of medicines as sildenafil and vardenafil, but tadalafil has a notably longer period of potential activity.
In the UK, tadalafil is available in authorised medicines in several strengths. Depending on the treatment plan, it can be taken when required before sexual activity or, for some patients, as a lower-dose daily medicine.
This guide explains how tadalafil works, how long it can remain effective, commonly used strengths, daily tadalafil, side effects, medicine interactions and how tadalafil differs from sildenafil.
What Is Tadalafil?
Tadalafil is a phosphodiesterase type 5 inhibitor, usually shortened to a PDE5 inhibitor.
It is mainly used to treat erectile dysfunction in adult men. Tadalafil is also used in some circumstances for symptoms associated with benign prostate enlargement and for pulmonary arterial hypertension, although treatment arrangements differ according to the condition.
For erectile dysfunction, tadalafil helps support the natural erectile response during sexual stimulation.
How Does Tadalafil Work?
During sexual stimulation, chemical signals cause blood vessels supplying the penis to relax. This allows increased blood flow into erectile tissue.
Tadalafil reduces the action of the PDE5 enzyme and helps this natural process continue more effectively.
Tadalafil does not automatically cause an erection. Sexual stimulation is still required for it to produce its intended erectile effect.
It also does not directly increase sexual desire.
Tadalafil in the UK
Tadalafil is an established medicine in the United Kingdom and is available in a range of authorised products.
It can be supplied in different strengths and treatment schedules depending on the patient’s needs, health and advice from a doctor or pharmacist.
Authorised tadalafil medicines are supplied within the UK medicines regulatory system, which covers areas such as product quality, manufacturing, approved patient information and ongoing safety monitoring.
Tadalafil 2.5mg, 5mg, 10mg and 20mg
Tadalafil medicines for erectile dysfunction can be available in several strengths, including:
- 2.5mg
- 5mg
- 10mg
- 20mg
The appropriate strength depends partly on how tadalafil is being used.
For treatment taken when required before sexual activity, an authorised product may recommend an initial dose of 10mg. Depending on effectiveness and tolerability, a healthcare professional may consider a 20mg dose.
Lower strengths such as 2.5mg or 5mg can be used in daily treatment regimens for appropriate patients.
A higher dose should not automatically be considered better. Increasing the dose can also increase the likelihood of unwanted effects.
How Long Does Tadalafil Last?
One of tadalafil’s best-known characteristics is its relatively long period of potential activity.
The medicine can remain effective for up to 36 hours after a dose in some patients.
This does not mean an erection lasts for 36 hours. Instead, tadalafil can continue to support an erectile response if sexual stimulation occurs during this period.
The actual response and duration vary between individuals.
When Should Tadalafil Be Taken?
When tadalafil is used as required for erectile dysfunction, authorised product information generally allows it to be taken from approximately 30 minutes before sexual activity.
Because tadalafil has a longer potential treatment window than sildenafil, precise timing immediately before sexual activity may be less important for some users.
The instructions supplied with the particular medicine should always be followed.
What Is Daily Tadalafil?
Some men who anticipate frequent sexual activity may be prescribed a lower dose of tadalafil every day rather than taking a larger dose only when required.
A commonly used daily regimen is 5mg tadalafil once daily, although a lower 2.5mg dose may be appropriate in some circumstances.
Daily tadalafil is taken at approximately the same time each day.
This approach means tadalafil is continuously present in the body and removes the need to time every dose immediately before sexual activity.
Whether daily tadalafil is appropriate should be determined according to individual health, frequency of sexual activity, tolerability and professional medical advice.
Does Food Affect Tadalafil?
Tadalafil used for erectile dysfunction can generally be taken with or without food.
This differs somewhat from sildenafil, where a substantial or high-fat meal can delay absorption and the onset of effect.
The reduced influence of food can be one practical reason some patients find tadalafil convenient.
Tadalafil and Cialis
Cialis is a well-known branded medicine containing tadalafil.
The relationship is therefore similar to other branded and generic medicines:
- Tadalafil is the active pharmaceutical ingredient.
- Cialis is a particular brand containing tadalafil.
Generic tadalafil medicines also contain the same active ingredient but are marketed under the ingredient name or another product name.
Tadalafil vs Sildenafil
Tadalafil and sildenafil are both PDE5 inhibitors used for erectile dysfunction, but there are several practical differences.
| Feature | Tadalafil | Sildenafil |
|---|---|---|
| Medicine group | PDE5 inhibitor | PDE5 inhibitor |
| Typical pre-activity timing | From about 30 minutes | Usually around 1 hour |
| Potential treatment window | Up to 36 hours | Shorter treatment window |
| Effect of food | Can generally be taken with or without food | A substantial meal can delay onset |
| Daily ED treatment option | Yes, for appropriate patients | Not normally used as a daily ED regimen in the same way |
Neither medicine is automatically better. Individual response, side effects, other medicines and treatment preferences all influence which option may be appropriate.
For more information about sildenafil, see our Sildenafil UK guide.
Why Is Tadalafil Sometimes Called the 36-Hour ED Medicine?
Tadalafil is sometimes associated with the phrase 36-hour ED medicine because its effect can remain useful for considerably longer than many other PDE5 inhibitors.
This extended period can allow greater flexibility because sexual activity does not necessarily have to occur within a short window after taking the medicine.
However, the 36-hour figure represents a potential treatment window, not a guarantee that every person will experience the same duration.
Common Tadalafil Side Effects
Like other medicines, tadalafil can cause side effects.
Common or recognised effects can include:
- Headache
- Indigestion
- Facial flushing
- Blocked or stuffy nose
- Muscle aches
- Back pain
- Dizziness
Not everyone experiences side effects, and their severity can vary.
Persistent or troublesome symptoms should be discussed with a pharmacist or doctor.
Serious Tadalafil Side Effects
Serious adverse effects are less common but can require urgent medical assessment.
Medical help should be sought for severe allergic reactions, significant chest symptoms, sudden serious visual or hearing changes, or an erection that becomes painful or lasts for several hours.
Anyone experiencing serious symptoms should not simply take another ED medicine or another tadalafil dose.
Tadalafil and Nitrate Medicines
An important safety issue involves nitrate medicines, which are commonly used to treat chest pain or angina.
Tadalafil should not normally be combined with nitrates because the combination can cause a dangerous reduction in blood pressure.
This is an important precaution shared with other PDE5 inhibitors including sildenafil.
Tadalafil and Poppers
Recreational products commonly known as poppers may contain nitrate or nitrite substances.
Combining them with tadalafil can result in a potentially dangerous fall in blood pressure.
The long duration of tadalafil makes this interaction particularly important to remember because the medicine may remain active well after the original dose was taken.
Tadalafil and Other Medicines
Tadalafil can interact with medicines other than nitrates.
Additional assessment may be required for people taking certain medicines used for:
- High blood pressure
- Heart conditions
- Enlarged prostate
- HIV treatment
- Fungal infections
- Some bacterial infections
- Epilepsy
Anyone taking regular medicines should check tadalafil suitability with a doctor or pharmacist.
Who May Need Extra Care With Tadalafil?
Tadalafil is not suitable for everyone.
Medical assessment can be particularly important for people with significant heart or circulation problems, low blood pressure, serious liver or kidney disease, certain eye conditions or a history of major cardiovascular events.
The suitability of ED treatment should therefore be considered individually.
Tadalafil and Alcohol
Drinking large amounts of alcohol can make erectile dysfunction more difficult and may also increase problems such as dizziness or low blood pressure.
Alcohol should therefore not be viewed as a way of improving tadalafil’s effect.
Anyone experiencing repeated erectile problems associated with alcohol use should consider the underlying cause rather than simply increasing ED medicine doses.
Tadalafil and Erectile Dysfunction Causes
Tadalafil can help manage erectile symptoms, but it does not necessarily treat the underlying reason that erectile dysfunction developed.
Persistent ED can be associated with:
- Cardiovascular disease
- Diabetes
- High blood pressure
- High cholesterol
- Hormonal conditions
- Smoking
- Excessive alcohol use
- Anxiety or depression
- Some prescription medicines
Repeated erectile dysfunction can therefore justify a broader health assessment even when tadalafil or another ED medicine improves the immediate symptom.
Tadalafil vs Other ED Medicines
Tadalafil is one of several PDE5 inhibitors available for erectile dysfunction.
Other important ingredients include:
- Sildenafil
- Vardenafil
- Avanafil
The medicines differ in treatment window, timing, food interactions, available strengths and suitability for individual patients.
See our ED Medicines by Ingredient guide for the broader comparison.
Tadalafil Frequently Asked Questions
What is tadalafil used for?
Tadalafil is mainly used to treat erectile dysfunction. It can also be used for certain symptoms of benign prostate enlargement and for pulmonary arterial hypertension under appropriate medical supervision.
How long does tadalafil last?
For erectile dysfunction, tadalafil can remain effective for up to 36 hours in some patients.
Does tadalafil cause an erection for 36 hours?
No. The 36-hour figure describes the potential treatment window. Sexual stimulation is still required, and an erection should not remain continuously present.
How quickly does tadalafil work?
Tadalafil can be taken from around 30 minutes before anticipated sexual activity, although individual response varies.
Can tadalafil be taken every day?
Yes. Lower-dose daily tadalafil can be appropriate for some patients. A common daily regimen is 5mg once daily, with a lower dose possible in certain circumstances.
Can tadalafil be taken with food?
Yes. Tadalafil for erectile dysfunction can generally be taken with or without food.
Is Cialis the same as tadalafil?
Tadalafil is the active ingredient in Cialis. Cialis is a branded tadalafil medicine.
Can tadalafil be taken with nitrates?
Tadalafil should not normally be combined with nitrate medicines because of the risk of a dangerous fall in blood pressure.
More ED Medicine Information
Return to our ED Medicines by Ingredient guide to compare tadalafil with sildenafil and other erectile dysfunction medicines.
For detailed sildenafil information, see our Sildenafil UK guide.
For our broader information about Kamagra, sildenafil and ED medicines in the UK, visit the Kamagra UK information homepage.
This page provides general educational information about tadalafil and erectile dysfunction. It does not replace individual medical advice, diagnosis or treatment from a doctor, pharmacist or other qualified healthcare professional.
