What does Cialis look like? PDE5 inhibitors only work in the presence of nitric oxide, which is released during sexual arousal, so you will need to be aroused for Cialis to work. There is no Cialis for women; only men should take it and its generic unbranded version, Tadalafil. How often can you take Cialis? Taking tadalafil alone is not enough to cause an erection. Do not drink grapefruit juice if you’re taking tadalafil for pulmonary hypertension. How many years can you take Cialis for?Vision changes. Muscle pain. But there are some differences. With Viagra, there is a higher risk of vision changes than with Cialis. Among people who take Viagra or sildenafil, 3% get blue vision that lasts a few hours. On the other hand, Cialis has a slightly higher risk of muscle pain than Viagra and vardenafil. About this medication. TADALAFIL (tah DA la fil) treats pulmonary arterial hypertension (PAH), a condition that causes high blood pressure in the lungs. It works by relaxing your . シアリスの成分「タダラフィル」の効果. 陰茎の海綿体には多くのPDE-5（5型ホスホジエステラーゼ）が存在していますが、通常時に勃起していないのはこのPDE-5の働きによるものです。. しかし、何らかの原因でPDE-5が増え過ぎると、勃起したいときにでき.