Before you mix Sildenafil and alcohol it’s important to be aware of the impact. Drinking a glass of wine or beer is not likely to impact or delay the effect of Sildenafil. However, drinking any more than this can make it more difficult to get an erection, so to get the best effects, it’s advisable not to drink too much. 

The effects of Sildenafil can last for up to six hours. However, how long the effects last depends on your age, health and dosage.  

Sildenafil helps you to keep an erection long enough to have successful sex. So it can help you keep your erection longer. We often recommend those who have ED and premature ejaculation (PE) to use ED medications before trying PE alternatives (Priligy and EMLA) as it may also improve their PE. But these ED medications wouldn't be used to treat PE if you are not also experiencing ED.

Sildenafil normally starts to work within 30-60 minutes. But don’t forget, you need to be aroused for it to work. 

Side effects are uncommon, but can include nausea, vomiting, back pain, diarrhoea and 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.

Sildenafil side effects can include vision changes. This is rare, however if you experience a sudden decrease or loss of vision, you should call your doctor or 111 straight away.  

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. Sildenafil dosage does not affect how quickly or for how long the treatment works.

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

Sildenafil works in the same way as Viagra. With the same active ingredient, they treat ED in the same way. When the dosage is the same, both medications are the same strength. You can find out more about Sildenafil vs. Viagra in our guide.  

No, you should take Sildenafil tablets in the dosage suggested by your clinician or as explained in the patient information leaflet. 

As previously mentioned it’s good to try an ED medication as many as 8 times before you make a judgement on if it’s working for you. If after this time you don’t think it is working, speak to your clinician and they may advise changing the dosage or trying something else.

If Sildenafil stops working for you, you should speak to your clinician. 

If you are taking alpha-blockers (such as doxazosin or tamsulosin), you should wait at least 6 hours between taking those and taking Sildenafil.

You will be unsuitable for Sildenafil if you are taking nicorandil or nitrates, such as GTN spray or isosorbide mononitrate tablets to treat angina.

It is important that you let us know which prescription, over-the-counter medicines and recreational drugs you are taking so that we can prescribe Sildenafil safely.

Some men find counselling helpful as a means of exploring and treating psychological causes for ED.

If Sildenafil does not work for you, contact us via your Patient Record so that we can discuss your alternative ED treatment options. View all our ED treatments.

You can request and pay for Sildenafil online, you don’t necessarily need a prescription. If you choose to buy Sildenafil over the internet, make sure that any online pharmacy is registered with the General Pharmaceutical Council (GPhC), any online doctor service is regulated by the Care Quality Commission (CQC) and all doctors are registered with the General Medical Council (GMC). 

When using our service you will need to complete an erectile dysfunction consultation, and if suitable, one of our clinicians will prescribe the treatment. You can then pay for your prescription online. 

Sildenafil can be accessed with or without a prescription online or from a pharmacy. It’s the active ingredient in Viagra Connect, an ED treatment that doesn't require a prescription. However, you will need to answer some questions to confirm your suitability for the treatment. Using our service, you can complete a quick online consultation.   

If you’d like to reorder Sildenafil, you can go to your Patient Record and select ‘reorder’.

If you’d like regular treatment, you can choose a subscription and save 15% off your consultation. 

Free delivery or convenient ParcelShop collection of your treatment is included each month, and there’s no contract to worry about, you can cancel any time.