Tadalafil: Uses, Strengths, Duration & Side Effects
Tadalafil is a medicine used to treat erectile dysfunction (ED). It belongs to the phosphodiesterase type 5 (PDE5) inhibitor family, alongside sildenafil, vardenafil and avanafil. Tadalafil is particularly known for its longer duration of action compared with several other ED medicines.
This guide explains how tadalafil works, its authorised UK strengths, how long its effects may last, possible side effects, important interactions and differences between authorised medicines and products marketed internationally.
What Is Tadalafil?
Tadalafil is the active ingredient in Cialis and various generic medicines. It works by inhibiting the PDE5 enzyme, helping blood vessels in the penis relax and improving blood flow during sexual stimulation.
Tadalafil does not automatically produce an erection or increase sexual desire. Sexual stimulation is still required for its erectile effects.
What Strengths of Tadalafil Are Available in the UK?
Tadalafil tablets authorised in the UK for erectile dysfunction are available in strengths including 2.5mg, 5mg, 10mg and 20mg.
The 2.5mg and 5mg strengths may be used for an appropriate once-daily treatment regimen. The 10mg and 20mg strengths are generally intended for use before anticipated sexual activity rather than continuous daily use.
For erectile dysfunction, authorised prescribing information generally recommends a maximum frequency of once per day. The appropriate dose depends on individual health circumstances, treatment response, other medicines and possible adverse effects.
Some products marketed internationally carry labels stating tadalafil strengths exceeding 20mg. These should not be interpreted as established safe or recommended ED doses in the UK. A product’s stated strength does not establish its quality, safety or regulatory authorisation.
How Long Does Tadalafil Take to Work?
Tadalafil may begin to work within approximately 30 minutes, although the time varies between individuals. It can generally be taken with or without food.
How Long Does Tadalafil Last?
One of tadalafil’s distinguishing characteristics is its duration of action, which may extend for up to 36 hours.
This does not mean that an erection lasts continuously for 36 hours. Instead, tadalafil may support erectile function in response to sexual stimulation during that period.
Tadalafil and Sildenafil: What Is the Difference?
Tadalafil and sildenafil belong to the same medicine class but differ in their pharmacological characteristics.
Sildenafil is commonly associated with an effect lasting several hours, while tadalafil may remain effective for considerably longer. Tadalafil also has authorised daily treatment regimens for certain patients.
The most suitable medicine depends on medical history, individual circumstances, possible interactions and advice from an appropriately qualified healthcare professional.
For more information about sildenafil, read our Sildenafil Guide.
For a detailed side-by-side comparison of sildenafil and tadalafil, including onset, duration, authorised UK strengths, treatment schedules and safety considerations, read our Sildenafil vs Tadalafil Comparison Guide.
Possible Side Effects of Tadalafil
Commonly reported side effects may include:
- Headache
- Indigestion
- Facial flushing
- Nasal congestion
- Back pain
- Muscle aches
- Dizziness
Serious adverse effects require urgent medical attention. These include chest pain, sudden loss of vision or hearing, and prolonged or painful erections.
Important Medicine Interactions
Tadalafil must not be taken with nitrate medicines or recreational nitrites commonly called poppers. Combining these substances can cause a dangerous fall in blood pressure.
Tadalafil must also not be combined with riociguat. Other medicines, including certain alpha-blockers, antibiotics, antifungal medicines and HIV treatments, may interact with tadalafil.
Because tadalafil remains active for an extended period, its interactions may remain clinically relevant after the immediate effects on erectile function have diminished.
Tadalafil and Alcohol
Excessive alcohol consumption can contribute to erectile difficulties and increase the likelihood of dizziness or low blood pressure while taking tadalafil.
Tadalafil Tablets and Oral Jelly Formulations
In the UK, authorised tadalafil medicines for erectile dysfunction are commonly supplied as tablets. Some products marketed internationally are described as tadalafil oral jelly formulations.
Different formulations are not automatically equivalent. Their absorption characteristics, quality standards and regulatory status may differ.
Cialis, Generic Tadalafil and International Products
Cialis is an established brand of tadalafil. Generic tadalafil medicines authorised in the UK must satisfy applicable regulatory standards for quality, safety and efficacy.
Products marketed internationally under other brand names should not automatically be considered authorised generic versions of Cialis. UK marketing authorisation applies to individual medicinal products.
Is Tadalafil Legal in the UK?
Tadalafil is used in medicines authorised in the United Kingdom. Certain authorised tadalafil products may be supplied following an appropriate pharmacy assessment, while others require a prescription.
However, the presence of tadalafil as an active ingredient does not automatically mean a particular product is authorised for UK supply.
Frequently Asked Questions
Is tadalafil the same as Cialis?
Tadalafil is the active ingredient in Cialis. Cialis is a brand name, while tadalafil is also available in authorised generic medicines.
Can tadalafil work for 36 hours?
Tadalafil may support erectile function for up to approximately 36 hours. This does not mean that an erection lasts continuously throughout that time.
Can tadalafil be taken every day?
Some authorised tadalafil treatment regimens involve daily administration. Whether daily treatment is suitable depends on the individual and should be determined through an appropriate medical assessment.
Can tadalafil and sildenafil be taken together?
Combining PDE5 inhibitors can increase adverse effects and should not be attempted without specific medical direction. Taking two different ED medicines together is not automatically safer or more effective.
Does a higher tadalafil strength always work better?
No. A higher strength does not guarantee greater effectiveness and may increase adverse effects. Treatment should follow the recommendations for the authorised medicine and the advice of a qualified healthcare professional.
Further Information
For independent medical information, visit the NHS tadalafil information pages.
This guide is intended for general educational purposes and does not replace advice from a qualified healthcare professional.