Side Effects of Sildenafil & How to Reduce Them

Dr. Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 07 Jun 2022

Sildenafil is a common unbranded treatment for erectile dysfunction (ED). It is known as a phosphodiesterase type 5 inhibitor (PDE 5) and contains the active ingredient sildenafil citrate. As with any medication, sildenafil can have some side effects.

Most sildenafil side effects are mild and do not last very long, especially when taking it for ED.


What are the most common side effects of sildenafil?

The most common side effects include:

  • stuffy nose
  • headache
  • nausea (feeling sick)
  • hot flush on your face or body
  • changes to vision, such as blurred vision
  • indigestion
  • dizziness

How to reduce the side effects of sildenafil

To reduce the risk of side effects when taking sildenafil, you should:

  • speak to your doctor before taking it if you use any other medications, especially certain medications for low blood pressure
  • drink plenty of water before taking sildenafil, especially if you felt faint or dizzy whilst taking it as dehydration can worsen these effects
  • avoid or limit your alcohol intake, as this can worsen or cause side effects like headaches or dizziness
  • take over the counter painkillers like paracetamol if you get a headache after taking sildenafil
  • only take as much sildenafil as you have been prescribed, as taking more will increase the risk of side effects

You need to be sexually aroused for sildenafil to work. You can increase the chances of it working on your current dose by understanding how to get an erection. If you think you need a higher dose to maintain your erection, speak to your doctor.

Does sildenafil have any long term side effects?

Most sildenafil side effects do not last long and are mild. They usually go away once you stop taking the medication. When taking sildenafil for ED, you should only be using the medication for sexual activity. This means you are unlikely to get side effects long term.

In rare cases, some side effects could be long term. For example, if you get a prolonged erection that does not go away after 4 hours, this could make your erectile dysfunction worse. You should get treatment straight away if this happens. Sildenafil can also cause vision problems but this is rare. This could lead to permanent or long term changes to your vision.

If you are worried about any long term sildenafil side effects, speak to your doctor.

Am I likely to get side effects from sildenafil?

You are more likely to not get side effects when taking sildenafil for ED. Your chances of getting side effects are increased if you take more than you should or do not take it as prescribed. Some things can interact with sildenafil, such as certain medications like nitrates. This could increase your risk of sildenafil side effects.

Before taking sildenafil, it is important to tell your doctor if you are taking any medication. They can make sure sildenafil is safe to take with your other medications. If your medications change whilst taking sildenafil, let your doctor know. If you get sildenafil side effects that do not go away or bother you whilst using sildenafil for ED, speak to your doctor.

Is sildenafil safe?

Yes, sildenafil is an effective and safe treatment for ED for most men. When ordering sildenafil through our website, you will be asked to complete a brief medical questionnaire. This will be checked by a doctor, to make sure it is safe. Some medical conditions and medications could make sildenafil unsafe. In these cases, you may be offered another treatment.

Are there any serious side effects from taking sildenafil?

Like any medication, there are some serious sildenafil side effects. It is rare to get serious side effects, but you should go to A&E or call 999 straight away if you get:

  • a severe allergic reaction, which includes symptoms such as breathing difficulties, dizziness, and swelling in the face or mouth
  • symptoms of a heart attack, such as pain in the chest, sweating, and dizziness
  • symptoms of a stroke, such as sudden numbness, confusion, and trouble speaking
  • bleeding from the penis
  • a serious skin reaction, which could cause skin peeling, blistering, and swelling
  • seizures (fits)
  • a sudden loss or serious decrease in vision

These may be more likely if you already have a medical condition. Our doctors will make sure that sildenafil is safe for you to take before they prescribe it. You should only take sildenafil as it has been prescribed to you. Only a doctor can increase your dose.

Sildenafil can sometimes cause chest pains during sexual activity. If this happens, sit down and try to relax. This usually goes away on its own but always speak to a doctor, or visit A&E if it gets worse or does not go away. Sildenafil can also cause prolonged erections. If you have an erection that lasts longer than 4 hours, you should speak to your doctor straight away or call 111.

Is there an alternative erectile dysfunction treatment that has no side effects?

There are no erectile dysfunction treatments that have no side effects. There may be another treatment that is more suitable for you if you have a medical condition or take a certain medication. ZAVA can prescribe a range of other erectile dysfunction treatments, such as:

  • Cialis, a branded version of tadalafil
  • Viagra, which contains sildenafil citrate and is a common brand name treatment for ED
  • tadalafil, which is another PDE-5 inhibitor

If you are not sure which ED treatment to choose, you can get an erectile dysfunction trial pack. This means you can try 3 different treatments to see which one works best for your ED and which gives you the least side effects. If you are not sure which ED treatment is best for you, speak to a doctor for free through your online account.

Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion
Accreditations: BSc, MBBS, MRCGP (2008)

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: 07 Jun 2022

ZAVA offers a convenient and discreet service to help men improve their erectile dysfunction. There are a number of treatments you can consider. Continue to our erectile dysfunction service page to learn about the treatment options available.

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