The Independent Pharmacy

Tadalafil: How It's Different To Viagra

Scott McDougall
Scott McDougallMPharmDirector & Registered Manager

Reviewed on 30 Nov 2023

Since 1998 one name has been synonymous with the treatment of Erectile Dysfunction (ED): Viagra.

However, despite its ubiquity, Viagra is not the only form of medication available to treat ED. Included among the other options is Tadalafil.

While it shares with Viagra the purpose of treating ED, Tadalafil is not the same product and, as such, there are differences between the two.

In this article, we look at both Viagra and Tadalafil and run through how the latter differs from the former.

What is Viagra?

Viagra is the brand name of the drug sildenafil. Sildenafil is a drug that is used to treat ED and it works by increasing the flow of blood to your penis.

What is Tadalafil?

Tadalafil is a drug used to assist the treatment of ED. It addresses ED by helping to increase the blood flow to your penis and is sold under the brand name Cialis. (It can also be bought for cheaper as a generic drug). Read more about Tadalafil and how it works.

How do Tadalafil and Viagra differ?

Drug vs brand

While both Tadalafil and Viagra are both forms of treatment for ED, one is a drug and the other is a brand.

It is important to note that they are both different drugs: tadalafil is a drug, while Viagra is the brand version of the drug Sildenafil.

This means that, though both have the same purpose, they are not the same chemical product.

Length of effectiveness

Tadalafil works for about 36 hours, making it a drug that is often used with a degree of pre-planning – you know that you require ED medication and plan to use it accordingly.

Sildenafil, the active drug in Viagra, works for around 8 hours, giving it a lifespan of 22% of that of tadalafil. Click here if you are interested in finding out more about how long Sildenafil lasts.

Due to its shorter period of effectiveness, Viagra is often used as an unplanned ED treatment.

Factors which reduce the effectiveness

Food is known to reduce the effectiveness of Viagra. However, food does not erode the success rate of Tadalafil.

Dosage of tablets

While both are sold in tablet form, the dosages differ:

  • Tadalafil is sold in 10 mg and 20 mg doses
  • Viagra is sold in 25 mg, 50 mg, or 100 mg doses

Similarities between Viagra and Tadalafil

Both are PDE5 inhibitors

Beyond their shared purpose, you should note that both Tadalafil and Viagra are phosphodiesterase type 5 (PDE5) inhibitors – Tadalafil by virtue of being a drug which is a PDE5 inhibitor, and Viagra due to its main active drug being a PDE5 inhibitor.

Side effects

This means that they each share the same side effects. With these being:

  • Backache
  • Blurred vision
  • Dizziness
  • Feelings of nausea
  • Headache
  • Hot flushes, such as facial flushing
  • Indigestion
  • Runny or blocked nose

Read more about Tadalafil side effects here.

Effectiveness

Both Tadalafil and Viagra have been shown to be 60-70% successful in treating ED.

Availability

In the UK you are only able to purchase either Tadalafil or Viagra if you have a prescription. This means that both are available to buy from an online pharmacy after an initial consultation, through your GP, or via a high street chemist with a prescription.

While both Tadalafil and Viagra are used as ways of treating ED, it is important to know that they are not one and the same.

They may share the same purpose, but they do not share the same active drug and as a result, they have different lengths of effectiveness.

You will have to decide which of the two is the product that best meets your needs.

Read next our comparison of Viagra Connect vs Viagra.

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