Viagra is the most popular of the three drugs used to treat erectile dysfunction (ED), which are Viagra, Levitra and Cialis. Viagra itself comes in different dosages, depending on a patient's individual needs. While Viagra, Levitra and Cialis operate in a similar fashion, by allowing more blood into the penis, there are several minor differences that may make one preferred over the others.
Viagra
Viagra was the first of three erectile dysfunction drugs to be released, which has helped with its popularity. Viagra was granted United States Food and Drug Administration approval to treat erectile dysfunction in 1998.
A typical starting dose of Viagra is 50mg, but there are 25mg and 100mg tablets available, as well. The 25mg tablets are usually for those over 65 years old or with liver or kidney problems. The 100mg tablets typically work better than those containing smaller dosages, but may not be needed if the smaller dosages are sufficient.
Levitra
Levitra was the second of the three erectile dysfunction medications released, having been introduced in 2003. Levitra quickly made a splash in the market through an aggressive advertising campaign and made a good dent in Viagra's share of the market.
Levitra is available in 2.5mg, 5mg, 10mg and 20mg tablets. The suggested starting dose is 10mg.
Cialis
Cialis, the last of the three ED drugs to be released, is different from the other two drugs in that there are two different versions, a low-milligram version that is designed to be taken every day, as well as a higher dose that is taken 30 minutes before sex.
The higher dose of Cialis lasts up to 36 hours, while the other two drugs last up to four hours. The dose for everyday usage is 2.5 or 5mg. The doses for 36-hour use are 5mg, 10mg or 20mg.
