Cialis is a longer-acting version of the well-known Viagra. You can take it when you need it, or you can take a low-dose pill every day. There are several instances in which you should not take Cialis online UK, and you should speak with your doctor about whether it’s safe for you. Cialis is a longer-acting option that some men prefer over other ED treatments. First, Cialis works relatively quickly but not as fast as Viagra. It is a fact that the effects of Cialis last noticeably longer than the effects of Viagra.