Sildenafil

• What is sildenafil?

  Phosphodiesterase inhibitor
• What is the pharmacology of sildenafil?

  Target: Phosphodiesterase 5

  Activity: Antagonist
• What are the indications of sildenafil?

  Pulmonary arterial HTN

  Erectile dysfunction
• What are the side effects of sildenafil?

  Diarrhoea

  Nausea

  Skin reactions
• MOA - sildenafil

  Selectively inhibits cGMP-specific phosphodiesterase type 5 (PDE5) -> increased cGMP levels -> smooth muscle relaxation -> increased flow of blood

  PDE5 is in the corpus cavernosum & in the pulmonary circulation.
• What is the interaction of nitrates with sildenafil?

  Both are vasodilators

  Can cause a life-threatening drop in BP is used together