ED

Question 1

Treatment goals of male sexual dysfunction

Answer 1

1. Imrprove libido
2. Acquire and sustain erection
3. Treat premature ejactulations

Question 2

Main class of drugs for ED

Answer 2

Phosphodiesterase-5 inhibitors

Question 3

Dose of sildenafil and dosing instructions

Answer 3

50 - 100 mg, 30 mins before sex
- Duration of action: 4h

Question 4

Dosing of vardenafil and tadalafil and their dosing instructions

Answer 4

10 - 20 mg one hour before sex

Vardenafil duration of action: 4h
Tadalafil duration of action: 36h (very long)

Question 5

Monitoring for PDE-5 inhibitors?

Answer 5

1. Blood pressure
2. Pulmonary edema (due to decreased BP, may cause fluid accumulation)

Question 6

Significant drug interactions with PDE-5 inhibitors and management

Answer 6

1. Nitrates: severe hypotension. Space 48h apart
2. Antihypertensive: may lead to hypotension
3. CYP3A4 modulators (increase or decrease concentrations of PDE-5 inhibitors)

Question 7

Administration counselling points for PDE-5 inhibitors?

Answer 7

• Take on empty stomach
• Avoid high-fat meals as it may decrease absorption
• Take xx hours before sexual intercourse
• Stimulation is still needed for erection

Question 8

Which PDE-5 inhbitors require renal, hepatic, or both dosing adjustments?

Answer 8

1. Sildenafil: Both (CrCL < 30, half initial dose)
2. Vardenafil: only if moderate hepatic impairment
3. Tadalafil: Both (need to adjust starting CrCL ≤50, avoid use in CrCL < 30)

Question 9

Side effects of PDE-5 inhibitors?

Answer 9

1. Hypotension
2. Visual disturbances (except avanafil)
3. Flushing, headache, dyspepsia, etc.

Question 10

Mechanism of action of alprostadil

Answer 10

Prostaglandin E1 agent, directly effect vascular smooth muscle and stimulate corporeal veno-occlusive mechanism

Question 11

Route of administration and dosing of alprostadil

Answer 11

Intracavernous route. Initial 2.5 mcg
- If no response: increase to 7.5 mcg, then 5-10 mcg increaments
- If partial response: Increase to 5 mcg, then 5-10 mcg increaments

Intraurethral route: Initial 125-250 mcg, increase or decrease stepwise until erection achieved

Question 12

Dose limits of alprostadil

Answer 12

Maximum 3x/w, spaced at least 24h between dose

Question 13

Therapeutic monitoring of alprostadil

Answer 13

Ensure erections are firm and lasts for <1h