But unfortunately a lot of the research is flawed – according to a new review of the evidence.

Of the 14 studies included in the review, 11 found that the medications helped to extend the length of time men could have intercourse before orgasm. But Dr. Anastasios Asimakopoulos, lead author of the report, urged caution in interpreting the findings. The drugs, which go by the brand names Viagra, Levitra and Cialis, are intended to treat men who have problems getting and keeping an erection.

The interest has arisen in the use of these drugs for premature ejaculation, because one of the side effects of using, Viagra, Levitra and Cialis is a delay in ejaculation. Ejaculation problems are quite common, with an estimated 20-30% of men in England experiencing at least one episode during their lifetime.

The three types of ejaculation problems are: Premature ejaculation, retarded ejaculation, retrograde ejaculation. Premature ejaculation is the most common type of ejaculation problem. It is where you ejaculate too quickly during sexual intercourse. Many men are unsure about how long ‘normal’ sex should last before ejaculation.

 A study involving around 500 couples from five different countries found that the average time was just under, five and a half minutes. However, in reality, it is up to the individual and their partner who decide whether or not they are happy with the time that it takes for him to ejaculate. Retarded ejaculation is a persistent or recurring delay in achieving ejaculation, or an inability to achieve ejaculation during sexual activity, even though you want to and your erection is normal.

Retrograde ejaculation is a rarer type of ejaculation. It occurs when sperm is ejaculated it travels backwards into the bladder. Men will experience the feeling of an orgasm but produce no or very little semen. The condition does not pose a danger to your health, but it can affect ability to father a child.

With treatment, the outlook for both premature and retarded ejaculation is generally good. There are a range of treatments and medication that can be used to restore normal ejaculation. Antidepressants such as Priligy and Prozac and other selective reuptake inhibitors may be helpful because one of their side effects is to prolong the time it takes to reach ejaculation. If you have an ejaculation problem, you will usually become aware of it through your own sexual behaviour or through discussion with your partner. The next step is to visit your GP who will discuss the problem with you, and either examine you or refer you to a specialist.