Sildenafil is a medicine used by men to treat erectile dysfunction (also called impotence), a disorder whereby a man cannot achieve or has difficulty in keeping an erection hard enough for sexual action. This medication is due to come off patent in 2013 in the European Union so this could lead to substantial price reductions for this popular lifestyle medication.

What is Sildenafil?

Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor. This medicine does not work directly on the penis but on the mechanism that causes an erection during sexual arousal.  When sexually aroused, a naturally-occurring chemical in the body called nitric oxide causes the blood vessels in a man’s penis to relax and open. This enables blood to run in to the penis, fill the tissues, and make it distend. Sildenafil works by raising the level of this natural chemical, thereby relaxing the blood vessels in the penis, leading to an erection.

How to use Sildenafil

You must take sildenafil exactly as explained by your doctor. Sildenafil is taken one hour before you intend to have sex. It usually takes from 30 minutes to one hour to take effect. Sildenafil can be taken before or after a meal, but it may take longer to take effect after a heavy meal or after drinking too much alcohol. It should not be used with any other treatments for erectile dysfunction.

The tablets must be swallowed whole with a glass of water and must not be taken more than once daily. You usually start with a 50 mg dose of sildenafil. The maximum dose is 100 mg and a higher dose will not be more effective. Make an appointment with your doctor if sildenafil does not enable you to have an erection or complete sexual intercourse, or if you feel that the tablet strength is too much for your needs. Do not take more tablets than what your doctor has recommended and tell your doctor if you do.

Who can use Sildenafil?

Sildenafil is only for men who have erectile dysfunction. This medicine is not for women or for children and adolescents. Sildenafil should only be used when you are sexually stimulated otherwise it will not work.

Sildenafil can lower your blood pressure and so it is very important to let your doctor know if you take medicines known as nitrates. You may be taking nitrates if you suffer from chest pain (angina). Similarly, you should also let your doctor know if you take drugs containing nitrites (such as ‘poppers’ that are often taken for recreational purposes). Other medicines that you should inform your doctor about include protease inhibitors (an HIV treatment) and alpha blockers (treatments for high blood pressure and prostate enlargement) as you may need a lower dose of sildenafil.

You should not take sildenafil if you are allergic to it or to any of the other tablet ingredients. Your doctor will want to know if you have an injury or deformity of your penis or Peyronie’s disease. Also mention if you suffer from heart problems, heart disease, low blood pressure, or if you have had a heart attack or stroke. It is important to tell your doctor if you have an inherited eye disease (such as retinitis pigmentosa) or have experienced loss of vision due to an eye condition (non-arteritic anterior ischaemic optic neuropathy or NAION). Other conditions you should tell you doctor about include sickle cell disease, bleeding problems, stomach ulcers, leukaemia, and bone marrow cancer.

Sildenafil side effects

Side effects experienced with sildenafil are usually mild to moderate and do not last long. Common side effects with sildenafil use include headache, flushed face, indigestion, visual disturbances (such as colour tinge, sensitivity to light and blurred vision), blocked nose and feeling dizzy.

It is important to contact your doctor straight away if you get chest pains either during or after sexual intercourse or if you suddenly have a loss of vision. Prolonged and painful erections may occur. If your erection lasts for more than four hours, again you must immediately seek medical attention.

At the current time, Viagra is the only licensed product for erectile dysfunction that contains this active ingredient but this will change when the patent expires. We expect a plethora of suppliers to be applying for licenses to manufacture and sell sildenafil as a generic product in the EU, which is a massive market for pharmaceuticals.

You can read more about sildenafil here -

Update: What is Sildenafil’s current patent status in the UK and other territories?

The pharmaceutical company that holds the patent for Sildenafil is Pfizer.

The first country where Viagra’s patent expired was New Zealand. Sildenafil came off patent in 2011. However, Pfizer did not give up and managed to promote, market and sell its own brand of the generic medication: Avigra.

In the US, the patent is due to expire in April 2020. This is due to two reasons. First because Pfizer, the pharmaceutical company that holds the patent, has won a court trial against Teva that established the extension of the patent up to 2019. The company has also been granted the patent protection for six extra months because of an experimental trial for another medication that uses the active ingredient sildenafil.

In Canada the patent was to expire in 2014, but a court trial established that patent was invalid and has opened the market to generic brands in 2010. In November 2012 Pfizer has asked for a re-hearing to reconsider the court’s decision on the topic.

In the UK, the patent is due to expire on 21st June 2013.

Where can you get Sildenafil from in the UK?

Since Pfizer’s patent for sildenafil has expired, the market has opened up and many companies are now producing generic sildenafil. Nevertheless, Pfizer has also created its own generic version of sildenafil. Hence, men suffering from erectile dysfunction in the UK can now choose between 2 different generic versions of sildenafil. In order to get this medication, a prescription is still needed. It is useful to know, though, that there are online clinics, such as The Online Clinic, that are already able to sell the product starting from Monday, 24th June 2013, after a relevant medical consultation. You can find the link to The Online Clinic in the section above.