The proper medical term of male impotency is erectile dysfunction. This is a condition where the penis of the patient is not firm enough to make him indulge in a sexual intercourse. An erection is the result of complex chemical sequences of the body like nerve impulses in the brain, in the spinal column, and in the areas around the penis.

This is followed by the responses in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa---the two chambers of penis. Erectile Dysfunction in men occurs when this chain of the sequences is disrupted by any outside factor like any injury, disease or nervous disorder. The ED medication fights against these disruptions and relaxes the muscles of the penis and allows the corpora cavernosa to fill with excess blood.

The Erectile Dysfunction medication for the most part includes selective enzyme inhibitors especially sildenafil making the celebrated Viagra, vardenafil HCl making Levitra, and tadalafil making Cialis. There is also the yohimbine making Yohimbine and Yocon.

The chemical composition of these Erectile Dysfunction medications is meant to inhibit the enzymes that cause the condition of it and also increase the levels of a certain chemical factor in metabolism. This results in smooth muscles of the penis to relax. On the other hand the blood flow in the chambers of the penis is also enhanced. This makes the penis firmer and the process of sexual intercourse becomes possible.

These drugs are available by prescription and can be taken once daily to improve the sexual activities. The patients are often confused about the choice of the several types of ED medications. Are there any differences between these major three types of Erectile Dysfunction medications --- Viagra, Cialis and Levitra? If there is any difference, what is that?

All these drugs work on the same mechanism that is they increase the flow of blood in the penis and when the man receives sexual stimulation he can achieve an erection.

But the difference lies in their effect on the body; for how long the erection will last and how quickly the effect can be achieved vary from drugs to drugs.

Levitra's claim to fame is its longer lasting action; the effect of this drug is claimed to last for about 5 hours. With Viagra you will get a little shorter effect that spans for four hours. However, both the drugs will require at least thirty minutes to kick off your sexual passion.

But, the Cialis claims to beat both the Levitra and Viagra in its magical performance. Cialis, the latest to win the FDA approval, would take as little as fifteen minutes to ignite the fire and the flame is claimed to last for up to another 36 hours in most of the cases.

However the heart patients who regularly take nitrate drugs and the patients of benign prostatic hyperplasia under alpha-blockers medication are advised to inform their doctors about their current medication while seeking help for Erectile Dysfunction .