Monday June 24 2013
The blue diamond Viagra pill has become well known
Today the media reports that the patent on Viagra has come to an end. This means that other drug companies can now produce their own versions of the drug.
Viagra is the brand name the pharmaceutical company Pfizer uses for the drug sildenafil citrate, which is used to treat erectile dysfunction.
Viagra was designed to treat high blood pressure and angina. Researchers found that it was not particularly effective for either condition but that it did lead to sustained erections, as a result of temporarily increasing blood flow to the penis.
Manufacturers Pfizer have held the exclusive right to market the drug (known as a patent) for the past 15 years since it was licensed in 1998. Now that the patent has expired other pharmaceutical companies will be able to market their own versions of sildenafil citrate.
It is likely that the price of these unbranded versions (generics) will be lower, meaning that Pfizer will face competition for sales. They may have to drop their prices in response.
What does it mean when a drug comes off patent?
A patent is a form of intellectual property that protects new inventions. It covers how things work, what they do, how they do it, what they are made of and how they are made. It gives the owner of the patent the right to prevent others from making, using, importing or selling the invention without permission.
Medicines are controlled by patent legislation, meaning a particular company has the exclusive right to market a drug they have discovered and developed. Other companies are not allowed to make or market the same medicine until the patent expires.
Initially, when pharmaceutical companies discover a new drug they are issued with a supplementary protection certificate (SPC).
Standard patents in the European Union are valid for up to 20 years to allow time for the drug to be developed fully and studied in clinical trials.
However, when the drug is finally approved and given a licence to be sold, the SPC allows a further period of up to 15 years for the company to market the drug exclusively.
Viagra was first licensed in 1998 and had a 15-year exclusivity period that came to an end a few days ago.
The brand name (in this case Viagra) is the name given to the product by the original company who made the drug (in this case Pfizer). The generic name refers to the active ingredient in the drug (in this case sildenafil citrate). This is a ‘non-proprietary’ name, which means it is not protected by a patent and no company owns the right to this generic name. Once a patent has expired, other companies can produce their own versions of the drug and sell them under this generic name.
Although they contain the same active ingredient as the branded product, generic versions of the drug are usually cheaper because the research and development costs have been less.
The generic drugs can cost up to 80% less than the branded drugs, meaning that prescribing them can save the NHS a lot of money.
Two days ago the pharmaceutical company Teva UK issued a press release reporting that they had made a version of generic sildenafil. Kim Innes, commercial director of Teva UK, is quoted as saying: “Sildenafil is one of the highest profile generic launches of 2013 and we’re really pleased to have been able to supply this medicine to our customers from day one of the branded patent expiring.”
Patient information about Viagra (sildenafil)
Sildenafil (brand name Viagra) is licensed to treat erectile dysfunction. It is available in tablet form in three different strengths and is taken one hour before sexual activity, a maximum of once a day. It works to restore erectile function by increasing blood flow to the penis when there is sexual stimulation.
Who can use it?
Sildenafil is safe for most men with erectile dysfunction, although there are some men for whom the drug may be unsuitable. Because it causes the blood vessels in the body to dilate, the slight increase in blood pressure may mean the drug is unsuitable for those with a history of serious heart or liver disease.
You should always have an individual risk assessment from your GP or the doctor in charge of your care before you start taking sildenafil.
Sildenafil is not suitable for women or children under the age of 18.
Do not take sildenafil if you are taking medicines that contain nitrates as the combination may cause a potentially dangerous decrease in your blood pressure.
This also applies to amyl nitrites (poppers) – a recreational drug.
Side effects of sildenafil include:
- headaches and migraines
- flushing (redness)
- nausea (feeling sick)
- vomiting (being sick)
- a blocked or runny nose
- back pain
- vision disturbances
- muscle pain
Sildenafil is associated with a very small, rare risk of heart problems such as angina, heart attack or heart rhythm problems. This is more common in people with existing cardiovascular diseases, which is why men with cardiovascular disease must be assessed before being prescribed sildenafil.
Can I get sildenafil on the NHS?
Your GP can prescribe sildenafil as long as it is safe to do so. However, in some cases you may need to pay the full cost of the medication. The exact price depends on the dosage and your local pharmacy, but four Viagra tablets usually cost between £17 and £30. It is likely that now that the patent has expired the price of sildenafil will drop.
Currently, only men with the following conditions are entitled to the drug on an NHS prescription (meaning they only have to pay the prescription charge).
- multiple sclerosis – a condition that affects the body's actions and activities, such as movement and balance
- Parkinson’s disease – a condition that affects the way the brain co-ordinates body movements, including walking, talking and writing
- polio – a condition that can cause severe muscle paralysis (lack of movement)
- prostate cancer – the prostate is a small gland between the penis and the bladder
- a severe pelvic or spinal injury
- spina bifida – a series of birth defects that affect the development of the spine and nervous system
- certain genetic conditions, such as Huntington's disease
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.