Medical
Emergency
If you have a medical emergency, call 999 or NHS 111. Do not use this service.
Sildenafil citrate 25mg | from £3.44 per tablet
Sildenafil citrate 50mg Viagra | from £5.31 per tablet
Sildenafil citrate 100mg | from £5.94 per tablet
Key Features
- The most well-known erectile dysfunction treatment
- Taken one hour before sex, it can remain effective for up to four hours
- Gives a firmer and longer-lasting erection when aroused
Viagra has helped millions of men gain and maintain a long-lasting erection.
Key Information
The medicine | Viagra (sildenafil) |
| Taking Viagra | Take one tablet one hour before sex. Viagra works best when taken on an empty stomach. Positive effects can last between four to six hours. Never take more than one tablet within a 24 hour period. Avoid taking Viagra with more than one or two units of alcohol as alcohol can limit its effectiveness. |
| How it works | It works by increasing blood flow into the erectile tissue of the penis. Viagra does not have an effect on your sexual desire, but will improve your erection if you are sexually aroused. |
| Effectiveness | The majority of men will notice a firmer and longer-lasting erection. If you find that the treatment does not work, ask our doctors whether it would be appropriate to increase the dose or to try a different medicine. If Viagra doesn’t work for you first time round, it could nevertheless be more effective next time. Indeed, doctors advise trying all erectile dysfunction medicines eight times before giving up. |
| Side effects | Side effects are uncommon, but can include nausea, vomiting, diarrhoea and an allergic rash. They can also cause facial flushing, headaches, light headedness, nasal congestion, indigestion, a pounding heartbeat and blurred vision. |
| Nitrates and Viagra | Our doctors will not be able to prescribe Viagra if you are taking nicorandil or nitrates, such as GTN spray or isosorbide mononitrate tablets to treat angina. |
| Alpha-blockers and Viagra | If you are taking alpha-blockers, our doctors will advise that you leave at least six hours between taking your alpha-blocker and taking Viagra. |
About Viagra
How quickly does Viagra take effect?
Viagra, if taken on an empty stomach, should take effect in less than 60 minutes. It only works if you are sexually aroused. Viagra remains effective in the body for between 4 and 6 hours.
Does Viagra treat the underlying causes of erectile dysfunction?
Viagra will not resolve the underlying physical cause of your erectile dysfunction. However, it can help to improve your confidence if your ED is due to performance anxiety, thereby possibly improving your capacity to attain a natural erection in the future. As erectile dysfunction is often a symptom of other underlying conditions such as vascular disease, it is important to have the follow up tests we recommend to check your blood pressure, cholesterol, blood sugar and hormone levels, particularly if you are over the age of 40.
Alternative Treatments
Other Medicines
| Cialis | Sildenafil | Levitra | Spedra | |
| Key Information | Faster and longest acting | Same active ingredient as Viagra | Recommended for diabetics | Targeted and fast acting |
| View | View | View | View |
Psychological Therapy
Some men may want to try counselling to treat psychological causes of erectile dysfunction. Some sexual health clinics (also known as GUM clinics) offer this service if you are interested in counselling.