Viagra (branded Sildenafil)

Take one tablet 1hr before sex and works best on an empty stomach. Alcohol will limit Viagra's effectiveness. Do not combine Viagra with other ED medicines.

Viagra's active ingredient (sildenafil citrate) increases blood flow to the penis. It enables a firmer, longer-lasting erection if you are sexually aroused.

The treatment will not resolve the underlying physical cause of your ED or increase your sexual desire.

It usually takes 30-60 minutes to work for erectile dysfunction. It can be taken up to 4 hours before sex. Find out more about how long Viagra takes to work. 

Effects of Viagra can last for up to 4hrs. Never take more than one tablet within 24hrs.

Viagra treats ED in 60-70% of cases. If you have eaten a large meal or drunk more than 1-2 units of alcohol, you may find Viagra is less effective.

We advise trying an ED treatment 8 times before giving up, considering a higher dose, or seeking an alternative.

Some men who use Viagra might find that over time Viagra becomes less effective. However, there are lots of options for treating ED and Viagra does work for two thirds of the men who take it. 

It’s good to remember, you won’t instantly get an erection when taking Viagra. You will need to be sexually aroused for it to work. So don’t worry if you don’t instantly feel a difference, it can take 30-60 minutes to begin to feel the effect. You can take the tablet up to 4 hours before use.

Side effects are uncommon, but Viagra side effects can include:

• nausea
• vomiting
• back pain
• diarrhoea
• an allergic rash

Some men also experience facial flushing, headaches, light headedness, nasal congestion, indigestion, palpitations (racing heartbeat), and blurred vision. For full information on side effects and correct use, see the patient information leaflet.

ED medication such as Viagra is safe for people with healthy hearts. ED medications such as (sildenafil), Cialis (tadalafil) and Levitra (vardenafil) can be taken alongside most heart medications, but cannot be used alongside nitrates which are commonly used to treat angina. ED treatments can be used from six months after a heart attack but aren't recommended for people with low blood pressure. 

ED can be a symptom of underlying conditions such as diabetes, narrowing of the arteries or high blood pressure. ED can also be a side effect of some medications, including diuretics which are often used to treat heart-related conditions. Find out more about the signs of heart problems. 

The standard dose is 50mg. Depending on your age, height and weight, the cause and the severity of your ED, you may be prescribed a lower dose of 25mg, or a higher one of 100mg. Dosage does not affect how quickly or for how long the treatment works.

Higher doses come with an increased chance of developing side effects.