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What is sildenafil?

Sildenafil is medicine, taken in the form of a tablet, which can be used to treat symptoms of erectile dysfunction (ED) in men over the age of 18. Sildenafil is also sold under the brand name Viagra Connect.

Sildenafil works by helping to relax the blood vessels in your penis,1 allowing blood to flow into your penis when you get sexually aroused. Sildenafil will only help you to get an erection if you are sexually stimulated.

If you have a low libido, understanding the cause of this and getting help to increase your libido may change the way you think and feel about sex. This may then help improve your erection problems.

Talk to your doctor if you have low libido. There is support available that may help, including talking to a professional such as a psychologist or counsellor. Your doctor may be able to refer you for counselling, or you can refer yourself through the NHS.

Erectile dysfunction treatments at Well Pharmacy

Erectile dysfunction treatments are available from our online shop. Our products include sildenafil, Viagra Connect, Cialis, and tadalafil.

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How does sildenafil work?

Sildenafil works by helping to relax the blood vessels in your penis,1 this allows blood to flow into your penis as you become sexually aroused. It's important to note that sildenafil will only help you to get an erection if you are sexually stimulated.

How should I take sildenafil?

If you’ve decided to take sildenafil tablets to treat your erection problems you should swallow one whole tablet with some water up to four hours before you want to have sex.1 It's important that you don’t take more than one tablet a day.1

If you're not sure how to take sildenafil talk to your GP or a pharmacist. They’ll be able to give you more information and support.

How long does it take for sildenafil to work?

It usually takes 30 to 60 minutes for sildenafil to work.1 It's advised that you take one tablet about an hour before they want to have sex. But everyone is different and for some people, it may take more or less time to get an erection after taking sildenafil.

How long does sildenafil last?

Once you've taken sildenafil, it will stay active for up to four hours.3 It is important to remember that you will only experience an erection once you become sexually aroused.

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What are the common side effects of sildenafil?

You may experience some side effects from taking sildenafil. Side effects can include:1,2

  • headaches
  • sickness (nausea)
  • feeling dizzy
  • hot flushes
  • blurred vision.

Talk to your GP or a pharmacist if you experience any side effects after taking sildenafil. Find out more about all the possible side effects on the NHS website.

If sildenafil isn’t suitable for you, there are other treatment options available that may help. These include:

  • vacuum pump
  • injections
  • pellets
  • cream.

Is there a difference between sildenafil and Viagra?

The main differences between the two medications are that Viagra is a brand-name medication produced by Pfizer. Sildenafil is the active ingredient found in Viagra that is responsible for its positive function.

Another difference is that Viagra Connect is available to purchase over the counter whereas sildenafil needs to be prescribed for you.3,4

Frequently asked questions about sildenafil

How often can I take sildenafil?

Sildenafil is safe to take over a long period of time. The recommended starting dose is 50mg,3 and it is important that you don't take more than one tablet per day.

What is sildenafil used for?

Sildenafil is a medicine commonly known to treat erectile dysfunction. It can also be used to treat pulmonary hypertension, which is high blood pressure in the vessels that supply the lungs.2

If you need sildenafil to treat pulmonary hypertension it is important that you get a prescription from your GP. If you want to treat erectile dysfunction, sildenafil is available through the NHS,1 private prescriptions, or through an online pharmacy.

Where can I get further support and information?

As well as talking to your GP for information and support, there are also a number of organisations and charities offering support and information.

British Association for Counselling and Psychotherapy
01455 883 300
Find a registered counsellor or psychologist near you.

NHS Website
Information about erectile dysfunction.

Sexual Advice Association
Information for men about erectile dysfunction.

  1. Sildenafil (Viagra): medicine for erection problems. Published August 29, 2018. Accessed January 25, 2021.
  2. Sildenafil 50mg film-coated tablets - Summary of Product Characteristics (SmPC) - (emc). Accessed January 26, 2021.
  3. Sildenafil 50 mg film-coated tablets - Patient Information Leaflet (PIL) - (emc). Accessed September 29, 2021.
  4. Viagra 100 mg film-coated tablets - Summary of Product Characteristics (SmPC) - (emc). Accessed September 4, 2020.

Published: April 2022

Next review: April 2025

Reviewer: Mital Thakrar, Pharmacist

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