ED Flashcards
Treatment goals of male sexual dysfunction
- Imrprove libido
- Acquire and sustain erection
- Treat premature ejactulations
Main class of drugs for ED
Phosphodiesterase-5 inhibitors
Dose of sildenafil and dosing instructions
50 - 100 mg, 30 mins before sex
- Duration of action: 4h
Dosing of vardenafil and tadalafil and their dosing instructions
10 - 20 mg one hour before sex
Vardenafil duration of action: 4h
Tadalafil duration of action: 36h (very long)
Monitoring for PDE-5 inhibitors?
- Blood pressure
- Pulmonary edema (due to decreased BP, may cause fluid accumulation)
Significant drug interactions with PDE-5 inhibitors and management
- Nitrates: severe hypotension. Space 48h apart
- Antihypertensive: may lead to hypotension
- CYP3A4 modulators (increase or decrease concentrations of PDE-5 inhibitors)
Administration counselling points for PDE-5 inhibitors?
- 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
Which PDE-5 inhbitors require renal, hepatic, or both dosing adjustments?
- Sildenafil: Both (CrCL < 30, half initial dose)
- Vardenafil: only if moderate hepatic impairment
- Tadalafil: Both (need to adjust starting CrCL ≤50, avoid use in CrCL < 30)
Side effects of PDE-5 inhibitors?
- Hypotension
- Visual disturbances (except avanafil)
- Flushing, headache, dyspepsia, etc.
Mechanism of action of alprostadil
Prostaglandin E1 agent, directly effect vascular smooth muscle and stimulate corporeal veno-occlusive mechanism
Route of administration and dosing of alprostadil
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
Dose limits of alprostadil
Maximum 3x/w, spaced at least 24h between dose
Therapeutic monitoring of alprostadil
Ensure erections are firm and lasts for <1h