Erectile Dysfunction

Question 1

What are the pharmacologic treatment options for ED?

Answer 1

1. Identify drugs or other agents that may be causing the ED (like anti-hypertensives, antidepressants, etc)
2. Identify any underlying conditions (CV, smoking, HTN, dyslipidemia, obesity, etc) that may be causing the ED.
3. Prescribe a drug to treat the ED: PDE-5 inhibitor is first line. Sildenafil, vardenafil, tadalafil, and avanafil appear to be equally effective, but tadalafil has a longer duration of action.

Question 2

What are the PDE-5 inhibitors?

Answer 2

Sildenafil, vardenafil, tadalafil, and avanafil

Question 3

PDE-5 inhibitor MOA?

Answer 3

Penile/sexual stimulation activates NANC and endothelial cells, which produce NO, which activates gaunylate cyclase, which converts GTP –> cGMP. cGMP then activates myosin light chain phosphatase, causing smooth muscle relaxation and vasodilation. The PDE-5 inhibitors then inhibit the breakdown of cGMP, increasing the intracellular concentration of cGMP.

Question 4

Adverse effects and contraindications of PDE-5 inhibitors.

Answer 4

Contraindications:

• Men taking nitrates.
• Men taking alpha-adrenergic antagonists. If they are taking an alpha blocker, then they should take amsulosin (alpha blocker) with taladafil.

Adverse effects:

• # 1 adverse effects are H/A and flushing
• Visual changes. Blue vision and nonarteritic anterior ischemic otic neuropathy (NAION) with sildenafil.
• Priapism is an erection lasting more than 4 hours.