GU: Erectile dysfunction

Question 1

Erectile dysfunction can be the side-effect of what drug classes? (5)

Answer 1

1. Antihypertensives
2. Antidepressants
3. Antipsychotics
4. Cytotoxic drugs
5. Recreational drugs (like alcohol)

Question 2

Risk factors for erectile dysfunction include what? (5)

Answer 2

1. Sedentary lifestyle
2. Obesity
3. Smoking
4. Hypercholesterolaemia
5. Metabolic syndrome.

Question 3

What is the first-line drug treatment for ED?

Answer 3

An oral phosphodiesterase type-5 inhibitor.

They work by increasing blood flow to the penis but do not initiate an erection - sexual stimulation is required.

Question 4

How does inhibiting PDE-5 increase blood flow to the penis?

Answer 4

Normally PDE5 promotes the degradation of cGMP.

Less breakdown of cGMP = more cGMP leads to smooth muscle relaxation of the intimal cushions of the helicine arteries.

Question 5

Which ED drugs are short-acting and suitable for occasional use as required?

Answer 5

Avanafil
Sildenafil
Vardenafil

These are the short-acting drugs.

Question 6

Which ED drug is a longer-acting drug that can be used as required, but can also be used as a regular lower daily dose to allow for spontaneous (rather than scheduled) sexual activity or in those who have frequent sexual activity?

Answer 6

Tadalafil.

Question 7

A patient with ED should receive how many doses of an individual PDE-5 at the maximum dose before being classed as a non-responder?

Answer 7

5 doses.

Question 8

Patients who fail to respond to the maximum dose of at least how many different PDE-5 should be referred to a specialist?

Answer 8

at least 2

Question 9

What is alprostadil?

Answer 9

Prostaglandin E1

Question 10

What is the role of alprostadil in ED management?

Answer 10

Intracavernosal, intraurethral or topical application of alprostadil (prostaglandin E1) is recommended as second-line therapy under careful medical supervision. Intracavernosal or intraurethral preparations can also be used to aid diagnosis.`

Question 11

Alprostadil is associated with priapism: the manufacturers advise that patients should seek medical help if a prolonged erection lasting how many hours or more occurs?

Answer 11

Manufacturers advise that patients should seek medical help if a prolonged erection lasting four hours or more occurs; application of an ice pack to the upper-inner thigh (alternating between the left and right thighs every two minutes for up to ten minutes) may result in reflex opening of the venous valves.

Question 12

Aviptadil with phentolamine mesilate is used as an ED medication. How does this combination preparation work?

Answer 12

Aviptadil is a vasoactive intestinal polypeptide that acts as a smooth muscle relaxant.

Phentolamine is a short-acting alpha-adrenocepter antagonist that acts directly on vascular smooth muscle, resulting in vasodilation.

Question 13

The manufacturer of avanafil recommends what max dose every 48 hours with concurrent use of moderate inhibitors of CYP3A4?

Answer 13

100mg every 48 hours

Question 14

Avanafil should be avoided if the systolic blood pressure is BELOW what value or if blood pressure in general is ABOVE what value?

Answer 14

Below 90mmHg systolic.

Above 170/100mmHg in general.

Question 15

What are the most common side effects of PDE-5 inhibitors? (4)

Answer 15

1. Headache/dizziness
2. Flushing
3. Nasal congestion
4. Blue discolouration of vision