Mechanism of action of sildenafil is: (A) Inhibits PDE 2, (B) Inhibits PDE 4, (C) Inhibits PDE 5, (D) Inhibits PDE 3
Answer is C. Ans. is 'c' i.e., Inhibits PDE 5 * Sildenafil (Viagra) acts to increase cGMP by inhibiting its breakdown by phosphodiesterase isoform 5 (PDE-5).