Erectile dysfunction used to be one of the conditions that there was no true remedy for. It is still a condition that cannot be cured, but it can be remedied and managed with the use of ED medications such as Cialis, Viagra and Levitra. However, it didn’t used to be that way. Up until the year 1998 when Viagra got introduced to the market, the only remedies for ED were different folk remedies that, for a lack of a better word, sucked. None of them had any significant clinical effect on the ED and their efficiency, when observed, was mostly due to the placebo effect. However, in 1998, we got our first true FDA-approved medication that actually worked for patients with erectile dysfunction –Viagra.
Viagra made an impact like rarely a medication has in the past. Of course, it was the first and it worked, which was more than enough to make it one of the best sold medications of all times. It also addressed an issue that affected a large number of men and that was close to their hearts. And for a while, it stayed that way. Viagra has a share of more than 90% of all ED medications sold, with others being some less effective medications that some men still used. However, it wasn’t long before Levitra was introduced, a medication that was similar in function and efficiency to Viagra but whose effects lasted for a longer period of time, making it much easier to plan the taking of the medication.
And then, in 2003, Cialis came out, the medication we are concerned with and that we will compare to Viagra in this article. No disrespect to Levitra, but as Viagra is still the most recognized ED drug brand; we want to use that drug in particular for the comparison.
First of all, there are the similarities. Namely, both Viagra and Cialis have an effect on the same enzyme which is responsible for ED – the PDE5, one of many PDEs in our body, which is responsible for inhibiting cGMP, which is crucial for an erection. However, here is where we can already notice a 
difference between Viagra and Cialis. Namely, Cialis is more selective when affecting PDEs, as it does not affect the production and functioning of some PDEs as much as Viagra does, thus leading to much less side effects than Viagra is known to cause.
Of course, we also need to mention the biggest difference between these two medications and the one that makes Cialis a superior ED medication. Namely, Cialis lasts for much longer. Its beneficial effects can be felt for 36 hours, which is significantly longer than with Viagra, which makes Cialis a much more convenient medication to use, as you do not have to carefully plan out your sexual activities, and you are enabled to take things as they come once again.