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