This increased blood flow can cause an erection. This is not a complete list of side effects and others may occur. What special dietary instructions should I follow? If you miss a dose of Adcirca or Alyq, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. · Cialis is used in adult males.* It belongs to a group of drugs called phosphodiesterase 5 (PDE5) inhibitors. These drugs treat erectile dysfunction (ED) by relaxing blood vessels to increase. Cialis works by increasing blood flow to the penis to help a person get and maintain an erection. It also blocks the PDE5 enzyme, which enhances the effects of nitric oxide (NO). NO activates a. Used for Benign Prostatic Hyperplasia, Erectile Dysfunction. erectile dysfunction (ED) benign prostatic hyperplasia, or BPH). Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side effects of this medication include headache and indigestion. Tadalafil (Cialis) does interact with some medications.