The erectile dysfunction drug called Cialis is the second most popular erectile dysfunction medicine in the world after Viagra. It has as its main ingredient a compound called tadalafil that works in exactly that same way as Viagra's sildenafil by opening an dilating the blood vessels in the penile artery that supplies blood into the penis in order to maintain an erection.

Cialis is becoming increasingly popular, continually steals market share from Pfizer's Viagra and its sales are considerably up from last year. The marketing men of Cialis may great play of the fact that Cialis works longer than Viagra as Cialis can be working for up to 36 hours after you take the pill. This has led to the people of France nicknaming the drug 'Le Weekend Pill' and in fact it has had more sucess there than anywhere else in the world with a market percentage that exceeds Viagra.

The men of Cialis are still not absolutely sure why they have had so much success with Cialis in France but they are definitely not complaining and they say that they are looking ahead to the expected launch of the Cialis Once A Day tablets that could prove to be another selling bonanza for them. Being the first erectile dysfunction drug on the market obviously gave Viagra a head start on the sales race but the signs are that Cialis catching up and market analysts say that it is not completely out of the question that one day Cialis will be the world's No.1 erectile dysfunction drug and put Viagra in 2nd place.

Cialis comes in the form of a yellow pill and apart from the fact that it last for a longer time has no real differences to the Viagra effect. The great thing about the longer lasting duration is that men who suffer from erectile dysfunction say that they don't have to plan the exact time of their sexual encounters over say a weekend period and they know that the drug will be effective for the whole time and not just for 4 hours like Viagra.