The ultimate guide to Sildenafil side effects

Sildenafil is a little blue pill that is a game-changer for many people with erectile dysfunction (ED) and a few other conditions.

However, it produces some unwanted side effects, some of which can seem worrying.

The purpose of this article is to discuss how to manage or prevent Sildenafil side effects so you can continue standing tall with confidence.

So, what are the side effects of Sildenafil, and what can you do about them?

Headaches

Headaches are one of the most common side effects of Sildenafil, affecting more than 1 in every 10 people who use it (1). These occur because the drug increases levels of natural body chemical cGMP, which relaxes the smooth muscles in blood vessel walls, leading to vasodilation (opening of the blood vessels). This stimulates nociceptors for pain in the meninges (part of the brain) and sometimes the artery walls, leading to headaches.

This effect is most common for people already prone to headaches.

What to do about it

You can relieve symptoms by drinking plenty of water and staying hydrated.

You can also take over-the-counter painkillers like ibuprofen, which stop pain and reduce inflammation, or paracetamol which may also reduce symptoms

Feeling sick

Feeling sick (nauseous) is another possible side effect of Sildenafil. This affects more than 1 in every 100 people who use it (2).

Again, this effect is tied to the drug’s vasodilation effect. When blood pressure drops, it can stimulate the nervous system around the stomach, leading to the sensation that you are about to be sick.

This comes back to PDE5, as before. It’s also present in gastrointestinal smooth muscle, so blocking it could affect stomach action. This process, in turn, could then lead to the sensation of nausea.

What to do about it

If you feel sick after taking Sildenafil, try eating a light meal. A small quantity of healthy food can settle the stomach.

Avoid eating large or fatty meals before using Sildenafil. These foods can make nausea worse.

Flushing

Flushing, or getting a red face, is another symptom that can occur (3). Again, this follows in a common-sense way from the drug’s vasodilatory properties. When the blood vessels open up on the face because of cGMP increases, blood rushes to the surface of the skin and makes your skin red.

If you have rosacea, you may experience a more extreme response (4).

What to do about it

You can deal with Sildenafil-induced flushing by keeping your face cool with a fan or putting a damp cloth on your complexion to cool down. Wearing loose clothing may also help.

Usually, the immediate flushing fades as the body metabolises the drug. If flushing bothers you, you may want to consider alternatives.

Indigestion

Indigestion is another common side effect of Sildenafil. The drug’s relaxing effects can affect the lower oesophagal sphincter, causing stomach acid to flow back up into the gullet, which is the tube your food goes down.

What to do about it

The best option is to eat a healthy diet with plenty of fibre and low sugar and fat. This lifestyle reduces the risk of gastric reflux problems.

If that doesn’t work, you can try:

• Using an antacid
• Propping yourself up in bed before you sleep
• Trying an alternative ED treatment

Stuffy nose

Another side effect of Sildenafil is a stuffy nose. Sildenafil causes the blood vessels in the nasal cavity to widen, creating a congested nasal passage.

What to do about it

You can use a nasal decongestant or a simple saline spray. These reduce the immediate inflammation and help open up the airways more.

Steam inhalation or a steam sauna might also help.

Feeling dizzy

Sildenafil can also make some people feel dizzy because of its effects on blood pressure. Opening up the blood vessels means blood flows away from the brain more quickly, which can make people feel dizzy or faint.

The rate of dizziness is relatively low, affecting around 2 to 4 people in every 100 who use Sildenafil. However, it could affect you if you already have low blood pressure.

What to do about it

You can reduce the risk of feeling dizzy by reducing or eliminating alcohol intake (when using this treatment). You should also stay hydrated, this boosts blood volume and can counteract feeling lightheaded.

Blue vision

Lastly, Sildenafil may produce something called “blue vision”, where your vision has a slight blue tinge. You may experience this if you take too much of the drug.

What to do about it

You can also solve this by talking to your doctor about lowering your dose or trying an alternative treatment.

Serious side effects

Rarely, Sildenafil can cause serious side effects. These include:

• Seizures and fits
• Prolonged painful erections that last more than two hours

If these occur, call for help immediately or go to the A&E.

If you have chest pain, always call for an ambulance.

What about Tadalafil?

Tadalafil is another ED drug that works similarly to Sildenafil (by acting as a PDE5 inhibitor). However, it’s newer and slide effects are often reported to be milder.

For example, it may reduce the risk of headaches due to its longer half-life and slower peak. When Tadalafil gets into the body, it gets to work slower and lasts for longer (another reason a lot of people like it).

Finally, it could reduce stuffy nose symptoms. Again, slower onset means that it is less likely to expand suddenly the blood vessels in the nasal passages that lead to stuffiness (5).

Now you understand Sildenafil’s side effects

Now that you know how to reduce the side effects of Sildenafil, you should feel more confident using the drug. However, if you still find it isn’t working for you, you may have better luck with the newer Tadalafil.

References

1. Smith BP, Babos M. Sildenafil. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 [cited 2025 Mar].
2. Hatzimouratidis K. Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence. Clin Interv Aging [Internet]. 2006 Dec [cited 2025 Mar];1(4):403–14.
3. Goldstein I, Lue TF, Padma-Nathan H, Rosen RC, Steers WD, Wicker PA. Oral sildenafil in the treatment of erectile dysfunction. Sildenafil Study Group. N Engl J Med [Internet]. 1998 May 14 [cited 2025 Mar];338(20):1397–404.
4. Some Drugs May Worsen Rosacea [Internet]. [cited 2025 Mar].
5. Eardley I, Cartledge J. Tadalafil (cialisTM) for men with erectile dysfunction. Int J Clin Pract [Internet]. 2002 May 1 [cited 2025 Mar];56(4):300–4.