Erectile Dysfunction - Med/High Priority

Question 1

Describe the physiology of normal erectile function.

Answer 1

sexual stimulation

nitric oxide

cGMP

cavernosal smooth muscle relaxation

increased penile blood flow

normal penile erection

Question 2

What is ED?

Answer 2

inability to achieve or sustain an erection for satisfactory sexual activity
-also known as impotence

Question 3

What is required for normal erectile function?

Answer 3

sexual stimulation

Question 4

What is an erection a combination of?

Answer 4

continuous blood flow into the penis
limited blood outflow from the penis

Question 5

In which population is ED highly prevalent in?

Answer 5

aging men

Question 6

What does ED have a profound effect on?

Answer 6

intimate relationships
QoL
overall self-esteem

Question 7

What might ED be the presenting symptom of?

Answer 7

undetected CVD

Question 8

What are the risk factors for ED?

Answer 8

advancing age
diabetes
dyslipidemia
hypertension
obesity
metabolic syndrome
sedentary lifestyle
smoking
penile trauma
pelvic, penile, urethral surgery
prostatectomy and prostate radiotherapy
LUTS/BPH
illicit drug use
psychological conditions
drug causes

Question 9

What are some drug causes of ED?

Answer 9

opioids
5-alpha reductase inhibitors
SSRI, TCA, MAOI
lithium, phenothiazines
acute and/or chronic alcohol use
CBZ, phenytoin, barbiturates
spironolactone, thiazides, acetazolamide
digoxin
alpha-blockers, clonidine
beta-blockers
anti-androgen, GnRH analogues

Question 10

What are the goals of therapy for ED?

Answer 10

treat underlying conditions and reversible causes
address any contributing emotional factors
restore erectile capacity so that it is sufficient for predictable sexual intercourse
optimize non-pharm and pharm interventions
tailor treatment to personal preferences
improve quality of relationship

Question 11

What are the non-pharm measures for ED?

Answer 11

counseling:
-psychological factors
-partner issues
-economic factors
lifestyle modifications:
-weight loss
-regular physical activity
-smoking cessation
-tighter glycemic control
-reduce alcohol intake
treat comorbidities
vacuum erection devices

Question 12

Which drugs are PDE5i?

Answer 12

vardenafil
sildenafil
tadalafil

Question 13

What is the MOA of PDE5i?

Answer 13

inhibition of PDE5i located in penile vascular smooth muscle cells
-sub-erectile levels of cGMP are increased to critical erectile levels by delaying the degradation of this molecule by PDE5
=promoting smooth muscle relaxation in response to sexual stimulation

Question 14

Which PDE5i can be used daily?

Answer 14

tadalafil

Question 15

What are the key drug interactions of PDE5i?

Answer 15

nitrates
antihypertensives
3A4 inhibitors
cimetidine (sildenafil)
alpha blockers

Question 16

How is the PDE5i - alpha-blocker drug interaction managed?

Answer 16

space dosing

Question 17

Which AE are universal to all PDE5i?

Answer 17

headache
flushing
dyspepsia
nasal stufiness

Question 18

Which AE are unique to sildenafil and vardenafil?

Answer 18

visual symptoms (blue vision)
blurred vision
sensitivity to light

Question 19

Which AE are unique to tadalafil?

Answer 19

myalgia

Question 20

Which AE is unique to vardenafil?

Answer 20

QT prolongation

Question 21

What are the rare AE of PDE5i?

Answer 21

syncope
priapism
optic neuropathy

Question 22

Which agents are 1st line for ED for most pts?

Answer 22

PDE5i

Question 23

What is required for PDE5i to work?

Answer 23

sexual stimulation
-overall efficacy depends on mental arousal

Question 24

Which PDE5i is most effective?

Answer 24

similar efficacy within class

Question 25

Why should nitrates be avoided with PDE5i?

Answer 25

serious/fatal decrease in BP

Question 26

How is the nitrate - PDE5i drug interaction managed?

Answer 26

if nitrate required, it can be used: -24h after sildenafil & vardenafil -48h after tadalafil

Question 27

How do the PDE5i differ in their onset?

Answer 27

sildenafil & vardenafil: 30-60 min (peak: 1 hr) tadalafil: 60 min (peak: 2 hrs)

Question 28

How does the duration of PDE5i differ?

Answer 28

sildenafil & vardenafil: up to 8-12 hr tadalafil: up to 36 hr

Question 28

How does the t1/2 of PDE5i differ?

Answer 28

sildenafil & vardenafil: 4 hr tadalafil: 17.5 hr

Question 29

How do food interactions differ among PDE5i?

Answer 29

sildenafil & vardenafil: avoid with fatty meal tadalafil: no effect

Question 30

When do PDE5i require dose adjustments?

Answer 30

sildenafil: renal, hepatic, 65+ yrs old, 3A4i vardenafil: hepatic, 65+ yrs old, 3A4i tadalafil: renal, hepatic, 65+ yrs old, 3A4i

Question 31

What is the max daily dose of the PDE5i?

Answer 31

sildenafil: 100 mg/day vardenafil: 10-20 mg/day (formulation dependent) tadalafil: 20 mg/36-48h

Question 32

Which PDE5i has an ODT formulation?

Answer 32

vardenafil

Question 33

When do we switch PDE5i?

Answer 33

if tried first one 8 times and was unsuccessful -or add testosterone to improve ED

Question 34

What is the MOA of alprostadil?

Answer 34

prostaglandin E1 analogue -vasodilator that relaxes smooth muscle thereby allowing increased blood flow within the blood vessel

Question 35

What are the different formulations of alprostadil?

Answer 35

intracavernosal injection intraurethral pellet

Question 36

How is alprostadil used?

Answer 36

injection: -prn 5-10 mins before sexual activity -max once daily or 3x/week with 24 hrs between doses pellet: -prn 10-30 min before sexual activity -max twice/24hr

Question 37

What are drug interactions with alprostadil?

Answer 37

PDE5i

Question 38

What are AE of alprostadil?

Answer 38

penile pain dizziness headache urethral burning (pellet) priapism (4%) testicular pain (pellet) bruising/hematoma (injection) vulvovaginal pruritis in partner (pellet)

Question 39

What is the place in therapy for alprostadil?

Answer 39

2nd line

Question 40

Which formulation of alprostadil is preferred?

Answer 40

pellet -does not require injection

Question 41

What is a key side effect with alprostadil that pts must be warned about?

Answer 41

priapism (erection > 4 hrs) -medical emergency

Question 42

What are contraindications to alprostadil?

Answer 42

anticoagulation (injection only) history of priapism conditions that increase risk of priapism

Question 43

What are drug interactions of testosterone?

Answer 43

agents with BG lowering effects propranolol warfarin

Question 44

What are AE of testosterone?

Answer 44

acne or oily skin mild fluid retention stimulate prostate tissue breast enlargement worsening of sleep apnea decreased testicular size hair growth

Question 45

What is the role for testosterone in ED?

Answer 45

not as monotherapy - combo with PDE5i

Question 46

Is inadequate testosterone a common cause of ED?

Answer 46

not common -but testosterone may help improve ED

Question 47

Which topical version of testosterone has a lower risk of skin reaction?

Answer 47

topical gel has lower risk than patch

Question 48

Describe proper testosterone gel application.

Answer 48

avoid swimming, showering or washing the application site for 5 hrs following application avoid coming in contact with women who are pregnant or trying

Question 49

What is priapism?

Answer 49

erection lasting > 4 hrs -urgent referral