Dr. Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 21 Nov 2022

Tadalafil is a medication used to treat erectile dysfunction (ED) in men. It contains the active ingredient tadalafil, which is a phosphodiesterase type 5 inhibitor. It lasts for up to 36 hours after taking it, which is longer than most other ED treatments and is effective for 60-70% of people who take it.

It is the generic version of the branded medication Cialis and works in exactly the same way.

4 pack of tadalafil 10mg film-coated oral tablets

Key takeaways

  • Tadalafil is a treatment for erectile dysfunction in men. It contains the active ingredient tadalafil and is an unbranded medication.

  • Tadalafil works by relaxing the blood vessels, making it easier for blood to flow to your penis. This makes it easier to get and keep an erection hard enough for sex.

  • Tadalafil can be prescribed in 10mg or 20mg tablets. You should not take more than one a day.

  • Tadalafil can last for up to 36 hours and takes around 30 minutes to take effect.

How does tadalafil work?

Tadalafil is a PDE-5 inhibitor which works by relaxing the muscles in the blood vessels in your penis, allowing blood flow to your penis more easily. This makes it easier to get an erection providing you’re aroused. You need to be sexually aroused for tadalafil to work.

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How to take tadalafil

Tadalafil should be taken as prescribed by your doctor.

  1. You should swallow your tablet whole with water, with or without food.
  2. You should take tadalafil around 30 minutes before sex.
  3. Make sure you are sexually aroused when using tadalafil, such as engaging in foreplay with your partner before sex.

Avoid drinking alcohol whilst using tadalafil as it can make it harder to get an erection. It can also lower your blood pressure, which can increase side effects like dizziness. Grapefruit juice can also affect how well tadalafil works, so you may want to avoid it if you find tadalafil is not working as it should.

If tadalafil does not work the first time you use it, your body might need to get used to the medication. Try again the next day but do not take more than one tablet a day. Your doctor may recommend trying tadalafil up to 8 times before using a different ED treatment. They may also increase your dose to 20mg if you are using 10mg tablets.

How long does it take for tadalafil to work?

Tadalafil should start to work within 30 minutes, but it may take up to an hour to reach its full effect.

How often can you take tadalafil?

You can only take tadalafil once a day, so you must wait until the next day before taking another tablet. Taking more than one tablet will not make tadalafil more effectivebut may increase your risk of side effects.

How long does tadalafil last?

Tadalafil can last for 36 hours but this is different for every man. This can be affected by your age, whether you are sexually aroused, and the severity of your ED symptoms.

Dosage information

The starting dose of tadalafil for ED is 10mg. If 10mg tablets are not effective for you, your doctor can increase your dose to 20mg tablets. This depends on how often you need to take it,how well it works, and whether you get any side effects.

If you miss a dose, you can take tadalafil when you remember, as long as you have not taken another dose the same day.

Who can use tadalafil?

Tadalafil is suitable for men who have been diagnosed with ED by a doctor. You should not use ED treatments if you have not been diagnosed with ED because they will not be effective and could be unsafe. You must be over the age of 18 to use tadalafil.

Who should not take tadalafil

You should not take tadalafil if you:

  • have an allergy to any of the ingredients in the tablets
  • are taking nitrates, which are prescribed for chest pain
  • have serious heart disease or have had a heart attack in the last 90 days
  • are taking riociguat
  • have had a stroke within the last 6 months
  • have low blood pressure or uncontrolled high blood pressure
  • have ever had non-arteritic anterior ischemic optic neuropathy (NAION)

You should check with your doctor before taking tadalafil if you have:

  • liver or kidney problems
  • sickle cell anaemia
  • some cancers, such as leukaemia
  • a heart problem

Side effects of tadalafil

Tadalafil can have some side effects but most men do not experience any. If you do get side effects, they are likely to be mild and should go away once your body gets used to the treatment. If you get any serious side effects like a severe allergic reaction, call 999 or go to A&E.

Common side effects of tadalafil include:

  • back pain
  • muscle aches
  • headache
  • pain in arms and legs
  • blocked or stuffy nose
  • indigestion
  • redness in the face (facial flushing)

Uncommon side effects of tadalafil include:

  • stomach ache
  • dizziness
  • nausea or vomiting (feeling or being sick)
  • reflux
  • blurred vision
  • difficulty breathing
  • a prolonged erection, visit A&E or call 999 if your erection lasts longer than 4 hours
  • increased heart rate
  • pounding heartbeat
  • changes in blood pressure
  • nose bleeds
  • ringing in your ears
  • feeling tired
  • swelling of your hands, feet, or ankles

For more information on side effects check the patient information leaflet online or in the medication packet.

To reduce side effects you should avoid alcohol and grapefruit juice whilst taking tadalafil. You should also speak to your doctor if you take any other medications, as some medications can increase the risk of side effects. Only take tadalafil once a day and as prescribed by your doctor.

Generic tadalafil vs Cialis

Cialis is the branded version of tadalafil. This means it contains the same active ingredient and works in the same way. It has the same effect for ED, the only difference is the name. They both last for 36 hours but generic tadalafil is cheaper than Cialis. There is also a version of Cialis called Cialis Daily, which is taken every day and works constantly. This means you can always be ready to have sex when you’re aroused without worrying about taking a tablet.

Frequently asked questions

Is tadalafil available on the NHS?

Yes, tadalafil is available on the NHS if you have been diagnosed with ED. You can speak to your doctor if you want to try tadalafil.

Can you buy tadalafil over the counter?

No, tadalafil must be prescribed to you as it is only safe to take if you have ED. This means you must speak to a doctor to get tadalafil.

Can tadalafil tablets be split in half?

No, tadalafil tablets should only be swallowed whole with water. If you think you need a lower dose, speak to your doctor. They may recommend taking 10mg tablets or switching to a different ED treatment.

Why is tadalafil known as the ‘weekend pill’?

Tadalafil is sometimes called the ‘weekend pill’ because it lasts for 36 hours. This means if you take your tadalafil pill on Friday evening, the medication could have an effect for most of the weekend.

Is tadalafil the same as Viagra?

Tadalafil is similar in how it treats ED, but it is not the same as Viagra. Viagra contains sildenafil, which is another phosphodiesterase type 5 inhibitor. Viagra also increases blood flow to your penis but lasts for up to 4 hours, rather than 36.

Is tadalafil stronger than Viagra?

Tadalafil contains a different active ingredient than Viagra. This does not mean that tadalafil is stronger than Viagra, just that it can treat ED for longer. Both medications can help you get an erection but this does not change how hard your erection will be.

Does tadalafil make your penis bigger?

No, tadalafil can help you get and maintain an erection but cannot change the size of your penis.

Can tadalafil make you last longer in bed?

Tadalafil is not a treatment for premature ejaculation although it can help you to get erect. If you notice you are ejaculating quickly, you may be able to get premature ejaculation treatment such as Priligy.

Can tadalafil cause heart problems?

Tadalafil can have side effects such as an increased heart rate or pounding heart, but this does not mean it will cause heart problems. It may not be suitable if you already have a heart problem, but your doctor will discuss your options and make sure tadalafil is suitable before prescribing it.

Does tadalafil really last for 36 hours?

Tadalafil can last for 36 hours but this is different for every man. It is most effective when taken as prescribed and whilst avoiding alcohol. If you notice that tadalafil is not working as long as it should, speak to your doctor. They may be able to prescribe a higher dose, up to 20mg.

Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.

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Last reviewed: 21 Nov 2022

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