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Your guide to Sildenafil

Couple in bed after using Sildenafil

How Does Sildenafil Work?

Sildenafil is the generic alternative to Viagra and contains the same active ingredient. Sildenafil works in the same way as Viagra by increasing blood flow to the erectile tissues of the penis to make it easier for men with ED to get and maintain an erection. It is not an aphrodisiac and doesn’t enhance your libido, it will only work when you are sexually aroused. Sildenafil is a PDE-5 (Phosphodiesterase Type 5) inhibitor. Other medicines in the same family include Levitra (vardenafil) and Cialis (tadalafil).

How Do I Take Sildenafil?

You should take Sildenafil about one hour before sex and ideally on an empty stomach. Alcohol and food can impair it’s effect so it’s recommend you don’t drink more than one or two units of alcohol when taking Sildenafil. Alcohol can also increase the risk of side effects such as dizziness when you take Sildenafil as it can temporarily cause a lowering of your blood pressure. It should be taken without food or alcohol for the best results, as consuming a high fat or heavy meal will delay it's onset of action, as will drinking more than one or two units of alcohol. You must not take more than one tablet at any time and should not take more than one tablet in a 24 hour period. Sildenafil should not be taken within 24 hours of taking any other ED treatment. You should not take it unless you intend to have sex.

How Effective is Sildenafil?

Sildenafil can be very effective in helping men with ED to get and maintain an erection. It usually remains effective for up to four hours. This does not mean that your erection will last this long, rather that you will be able to get an improved erection more easily during this period of time if sexually aroused. The results vary for different men as the effectiveness of Sildenafil depends on the underlying cause of the ED, its severity, your level of anxiety and the degree of sexual stimulation a man experiences. It is advised in most cases you try it on at least eight different occasions before trying a different medication or increasing the dose (if safe and appropriate).  If Sildenafil does not improve your erection, it is worth discussing this further with a doctor and ensuring you have had the checks and tests we advise with your GP.

What are the Side Effects of Sildenafil?

The side effects associated with Sildenafil are usually mild to moderate and of a short duration. The most common side effects include: light headedness, headaches, facial flushing, a blue tint to your vision, a stuffy nose and/or indigestion. You should always read the patient information leaflet that comes with your medication before taking Sildenafil, for a full list of potential side effects and warnings.

If you experience any chest pain when using Sildenafil or your erection lasts for longer than four hours please contact emergency services and seek medical help immediately.

Other Medicines and Sildenafil

Sildenafil should not be taken if you are taking certain medicines due to serious and potentially life threatening interactions. It is extremely important that you let us know about ALL medicines you have or are taking if you use our service.

Nitrates: Do not use Sildenafil if you are taking Nicorandil or any Nitrate containing medication. Nitrates are found in some heart medications such as a GTN spray or tablets that you put under your tongue and isosorbide mononitrate/dinitrate used for angina, as well as in certain recreational drugs; in particular “poppers”, “room odorizers” and “aromas”. Nitrates can also be found in other medications so it's very important you list all medicines and recreational drugs you have or are taking when asked, this is because when combined with ED medications they can cause a serious and life threatening drop in your blood pressure which can be fatal.

Alpha-blockers: These include terazosin, tamsulosin, doxazosin, prazosin and alfuzosin. If you are taking alpha blockers then you must leave at least a six hour gap between taking the alpha-blocker and taking Sildenafil, otherwise the combination can cause a dangerous drop in your blood pressure.

This is not a full list of all the medication interactions - Sildenafil can interact dangerously with other medicines. Please list ALL the medicines you are taking when asked. If you subsequently start taking a new medication, before taking your Sildenafil please always check with our doctors first by sending a message via your Patient Record, to ensure the Sildenafil is still safe to take.

The Underlying Causes of Erectile Dysfunction

Sildenafil does not treat the underlying cause of erectile dysfunction. Often ED is a symptom of a more serious underlying physical health problem such as diabetes, high blood pressure,  high cholesterol or a hormonal condition. Vascular disease (narrowing of the blood vessels) is the most common underlying physical cause and therefore ED can an early warning sign of heart disease and stroke, particularly if you are over the age of 40. It is therefore really important that you have the tests and checks we advise with your doctor to identify any underlying health issues and risk factors so they can be treated.

ED can also be caused by psychological problems such as stress, anxiety and depression. Sildenafil can help improve your confidence and reduce the stress and anxiety resulting from having the ED itself. This can help break the vicious cycle of failure to get an erection.

If you think you have erectile dysfunction, click here to complete our free medical assessment or if you think Sildenafil may be the right treatment for you click here. Our doctors will then assess whether you are suitable for treatment.