When you buy ED medications you must understand difference between them.
so here some facts about most known drugs , which where approved for the treatment of ED by the Food and Drug Administration (FDA) :

Before You Take CIALIS Tadalafil

Never forget that CIALIS is a drug,
and that there are strict guidelines for using it effectively and safely.

Study: Viagra may help after heart attack

"Erectile dysfunction drugs can prevent damage in the heart not only when given before a heart attack, as we discovered previously, but also lessen the injury after the heart attack," said Rakesh C. Kukreja, a professor of medicine and chairman of cardiology at Virginia Commonwealth University.

Men buy Viagra without any hesitation today, making Viagra more popular than ever.So what is it about Viagra that has earned it so much reputation worldwide?

Apart from being the first treatment for erectile dysfunction, it was the only treatment for a long time. Men suffering from impotence got hope in the form of Viagra. Their sex life, their marital life, and other spheres of personal and professional life revived with the help of Viagra.

Finally, Viagra not only made erections better but also the lives of men.

Viagra, Levitra, Cialis or some other ED treatment drugs like Kamagra, Silagra, Zenegra or Caverta all work in the same principle i.e. increase blood flow to the penile tissues. After the infusion of any of these drugs in a patient's body, upon sexual arousal, blood flow to the penile tissues increases which helps one get penile erection and maintain it.

Impotence, or erectile dysfunction (male erecticle dysfunction, ED), can consequence from the whole inability to reach erection, an unconformable power to reach an erection, or the ability to only get a short erection. Reported to the National Institutes of Health (NIH) - 15 million to 30 million mens are affected by ED.

What is the risk factors for erectile dysfunction?
What are the causes of erectile dysfunction?

Erectile Dysfunction - Why Does it Happen?

Erectile Dysfunction is the inability to get and maintain an erection during the sexual stimulation. The persistent form of erectile dysfunction in men is impotence. Cialis has been a very successful drug and can obtain only by prescription. Cialis is very popular for its long lasting affects which may last for around 36 hours after the dose for this purpose only it is mostly called as 36 hour pill. Cheap cialis can be brought from online pharmacists.