Tadfil 20 mg may be safe for some adults when prescribed appropriately, but it is not suitable for everyone. Tadfil is generally marketed as a tadalafil medicine; check the package to confirm its active ingredient. What you should know For erectile dysfunction: Tadalafil 20 mg is generally used when needed before ***** activity, not as a daily dose. The usual daily dose is 2.5–5 mg. 10233 +1 Common side effects: Headache, facial flushing, indigestion, back pain, and nasal congestion. Do not take it with: Nitrate medicines such as nitroglycerin or isosorbide, or riociguat, because of the risk of a dangerous drop in blood pressure. Do not combine it with: Other erectile dysfunction medicines, such as sildenafil (Suhagra, Cenforce or Fildena), unless your doctor specifically advises you to. Seek emergency care for chest pain, sudden vision or hearing loss, or an erection lasting more than four hours.