Cialis, Lilly

• Name: Cialis, Lilly
  
• Effective substance: Tadafil
  
• Content: 4 tablets (20 mg/tab)
  
• Administration: oral tablets
  
• Known as: viagra, Adcirca, Tadacip

Although sildenafil, vardenafil, and tadalafil all work by inhibiting PDE5, tadalafil's pharmacologic distinction is its longer half-life (17.5 hours). Sildenafil and vardenafil are both 4–5 hours. So Cialis has longer duration of action, which is partly responsible for nick name: The Weekend Pill.