Functions by helping to relax the blood vessels in the penis, allowing blood to flow into the penis creating an erection. If you plan to use Cialis, you is going to take it 20-30 minutes before planned sexual activity. An erection is possible for upwards to 36 hours after taking it (this means the ability to have an erection may previous this long, nevertheless the real erections will only last a normal period of time). It can be taken as a daily low dose pill. Does Cialis have side effects? Typically the most common side outcomes with Cialis include: headache, indigestion, back pain, muscle aches, flushed skin, stuffy or runny nose. These types of side effects usually go away after a that same day. Very occasionally, Cialis can create a painful erection or an erection that won’t go away. In such a circumstance, and the erection takes more than 4 hours, you should Tadalafil 10 mg tablet cost go to the local emergency department. Prolonged erections can be dangerous.