Among the following, which of the following 5-PDE inhibitor has the longest duration of action?: (A) Sildenafil, (B) Vardenafil, (C) Tadalafil, (D) Udenafil
Answer is C. Ans. is 'c' i.e., Tadalafil o Tadalafil is the longest acting phosphodiesterase inhibitor used for erectile dysfunction. Its half life is 17.5 hours.