Erectile Dysfunction Flashcards
(56 cards)
1
Q
What is erectile dysfunction (ED)?
A
The persistent/recurrent inability to achieve or maintain an erection of sufficient rigidity to permit satisfactory sexual activity for at least 3 months
2
Q
Describe how an erection happens (2)
A
- When stimulated, ACh produces an erection through multiple pathways which ultimately increase the levels of cGMP, cAMP and nitric oxide.
- This results in smooth muscle relaxation which increases arterial blood flow, allowing the corpora to fill with blood
3
Q
What are some potential causes of erectile dysfunction? (4)
A
- Any abnormality in the vascular, hormonal, neurologic, or psychogenic system
- ~ 80% of ED cases related to organic disease
- Vascular
- Hormonal or
- Neurologic causes - <10% of ED cases are due to psychogenic factors
- Up to 25% of ED cases are medication-induced
4
Q
What are some risk factors for ED? (4)
A
- Age
- Lifestyle
- Tobacco
- Obesity
- Sedentary - Medical conditions
- Medications
5
Q
ED incidence is low in men <__yo
A
40 (increases with age)
6
Q
The most common cause(s) of ED are vascular. Meaning?
A
Disease states that compromise vascular flow to the corpora cavernosum can cause ED
7
Q
What are medical conditions associated with vascular causes of ED? (7)
A
- Diabetes
- Atherosclerosis
- HTN
- Renal disease
- Liver disease
- Excessive cig smoke
- Radiation (causing vascular damage)
8
Q
How is ED possibly a predictor of CAD? (3)
A
- ED and CAD are linked as they are both consequences of endothelial dysfunction, leading to restriction in blood flow
- ED in healthy men may be associated with early (subclinical) signs of CAD
- If person presents with ED, they should have BP, BG, and cholesterol checked
9
Q
Describe the relationship between ED, diabetes, and PDE5Is (3)
A
- ED is more prevalent in those with diabetes vs. those without; this is due to vascular and neurogenic mechanisms
- Risk related to duration and glycemic control - Occurs at an earlier age than in those without diabetes, and may be the presenting symptom
- The response to PDE5Is seems to be lower than in those w/o diabetes; higher doses are frequently needed
10
Q
Describe how ‘neurological’ issues can cause ED?
A
Sexual arousal causes nerve impulses to travel from the brain via the spinal cord to the genital region
11
Q
What are some conditions that impair nerve conduction to the brain? (3)
A
- Spinal cord injury
- Stroke
- Pelvic trauma, prostate surgery
12
Q
What are some conditions that impair nerve conduction to the penile vasculature? (6)
A
- Parkinson’s
- Alzheimer’s
- MS
- Epilepsy
- Diabetic neuropathy
- Alcoholic neuropathy
13
Q
____________ levels decline with age which can lead to decreased libido and secondary ED
A
Testosterone
14
Q
What is primary hypogonadism?
A
Can occur with normal aging process or surgical removal of testes
15
Q
What is secondary hypogonadism? (3)
A
- Can result from hypothalamic or pituitary disorders
- Hypo/hyperthyroidism
- May result from hyperprolactinemia (rarely)
- Drug induced causes (E.g. cimetidine, ranitidine, haloperidol, phenothiazines, buspirone, methyldopa)
- May also result from pituitary tumours, chronic renal failure
16
Q
What are some common psychogenic causes of ED? (4)
A
- Stress, performance anxiety
- Fear of STI’s or pregnancy, relationship issues
- Depression, other mental disorders
- Others
17
Q
How to treat psychogenic causes of ED?
A
Can try psychotherapy as monotherapy or as an adjunct to pharmacologic treatment
- Typically see a greater response than with organic disease
18
Q
What are some examples of drug classes that can cause ED? (7)
A
- Recreational drugs
- Psychotropics
- CV drugs
- 5 alpha reductase inhibitors
- Antiandrogens
- Dopamine antagonists
- Anticonvulsants
19
Q
What are the mechanisms by which some drugs can cause ED? (5)
A
- Anticholinergic activity
- Increased prolactin levels which inhibits T production
- Suppress T (diminished libido)
- Suppress psychogenic stimuli
- Reduce blood flow to penis
20
Q
Which of the following would NOT contribute to ED?
a. Smoking
b. Taking phenytoin for seizure disorder
c. Neuropathy
d. Well-managed hypothyroidism
e. Depression
A
d.
21
Q
How is ED diagnosed? (7)
A
- Sexual history
- Medical and surgical history
- Social history
- Medication history
- Physical exam – femoral pulses, prostate, anthropometrics, check for hypogonadism
- Standardized questionnaires
- Lab tests - sometimes
22
Q
What are the goals of therapy for ED? (3)
A
- Improve sexual satisfaction and intimacy
- Improve sexual quality of life
- Improve over all quality of life
23
Q
What are the non-pharmacologic treatments of ED? (4)
A
- Improve diet and exercise
- Smoking cessation
- Limit alcohol/recreational drug use
- Psychotherapy
24
Q
What are the 1st line meds for ED?
A
Phosphodiesterase Type-5 (PDE5) Inhibitors
(Convenience, efficacy, side effect profile)
25
What are the available PDE5I drugs? (3)
1. Sildenafil
2. Vardenafil
3. Tadalafil
26
What is the MOA of PDE5Is? (2)
1. Inhibit the PDE5 enzyme that degrades cGMP in the corpora cavernosa
2. This facilitates an erection by prolonging the action of cGMP which enhances nitric oxide-induced smooth muscle relaxation and vasodilation
27
What to know about the efficacy of PDE5Is? (5)
1. Efficacy improved with education
2. 1st dose can be efficacious, but can see improved success with successive doses
3. Should be tried 6-8 times before judging their success
4. Effect is dose-related (80% of effect at low dose; further 20% at high dose)
5. Failure with one PDE5I does not rule out a trial of another
28
What is peak onset of:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - 60 min
Tadalafil - 120 min
Vardenafil - 60 min
29
What is the duration of:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - ~4 hrs
Tadalafil - up tp 36 hours (weekender drug)
Vardenafil - ~4 hrs
30
How do high fat meals effect abosrption of:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - delays onset (no decrease in absorption)
Tadalafil - food has no impact
Vardenafil - high-fat meal decreases absorption
31
The PDE5Is are metabolized by?
CYP3A4
32
What are PDE5Is contraindicated with?
Nitrates
- Severe hypotension
- The vasodilator actions of nitrates (po, sl, transdermal) are profoundly amplified with concomitant use of PDE5Is and this could be fatal
33
How long until you can use a nitro spray after taking PDE5Is?
With sildenafil and vardenafil, wait at least 24 hours
With tadalafil, wait at least 48 hours
34
What are the other drug interactions to be aware of with PDE5Is? (3)
1. CYP3A4 inducers and inhibitors
2. Non-selective alpha1-blockers (particularly terazosin/doxazosin): may experience further hypotensive effects - recommended to space dosing by 4-6hrs if used these together
3. Antihypertensives?? - OK as long as BP is fine
35
How are the following dosed:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - prn
Tadalafil - prn or daily
Vardenafil - prn
36
What to know about renal impairment and using the following:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - decrease dose in mild-moderate. Not data for <30ml/min
Tadalafil - no adjustment required
Vardenafil - no adjustment required
37
What to know about hepatic impairment and using the following:
Sildenafil
Tadalafil
Vardenafil
Sildenafil - mild to moderate = decrease dose, max of 3x/week. Do not use in severe
Tadalafil - mild to moderate = 5mg up to a max of 10mg. Do not use in severe
Vardenafil - Do not use in moderate to severe impairment
38
PDE5Is are generally well tolerated, but what are some of the most common ADEs? (6)
1. Headache
2. Flushing
3. Dyspepsia
4. Dizziness
5. Rash
6. Rhinitis/nasal congestion
39
What is a tadalafil-specific ADE?
Back and muscle pain
40
What are the visual ADEs of PDE5Is? (2)
1. Blurred vision, ↑ light sensitivity
2. Loss of blue–green differentiation (up to 2-3%; dose-related; Sildenafil > vardenafil > tadalafil)
41
What are the serious but rare ADEs of PDE5Is? (5)
1. Sudden unilateral hearing loss: post-marketing reports
2. NAION (nonarteritic anterior ischemic optic neuropathy) -
sudden, unilateral, vision loss
- Those at risk of NAION should be evaluated by an eye doc first
3. QT prolongation with vardenafil
4. Priapism
5. Chest pain
42
What is the main 2nd line medication for ED?
Alprostadil
43
What is the MOA of alprostadil?
Stimulates increased production of cAMP and causes smooth muscle relaxation of tissues in the corpora & restricts venous outflow
44
What are the 2 dosage forms of alprostadil?
1. Intracavernosal injection
2. Intrauretheral insert (not in Canada anymore)
45
How quick is onset of alprostadil injection?
How long is duration?
- Onset within 10 mins
- Duration ~1 hour or less
46
What are the ADEs of alprostadil? (5)
1. Pain
2. Dizziness
3. Decrease HR
4. Headache
5. Hypotension
47
What cautions to be aware of with alprostadil? (3)
1. Anti-HTNsives
2. Vasodilators
3. Alcohol
48
What are 2 'other' medications that can be used for ED? (but not used much, if at all, these days)
1. Papaverine
2. Phenotolamine
49
What is the MOA of phentolamine?
Non-selective alpha-blocker; it increases cholinergic tone leading to improved cavernosal filling
(Used in combination only. Comes from compounding pharmacy)
50
What are 2 herbal products (with limited evidence) people try for ED?
1. Yohimbine
2. Korean Red Ginseng
51
What is a non-pharm device to help with ED? How does it work
A vacuum erection device
- A plastic cylinder is placed over the penis, the pump is activated to produce vacuum pressure, and arteriolar blood is drawn into the corpora cavernosa.
- A band is placed at the base of the penis to prevent drainage - remove within 30 mins
52
True or False? Treatment options for female sexual dysfunction is as robust as for ED?
False - much more limited
53
Although never really dispensed, what is a medication that can be used to treat generalized hypoactive sexual desire disorder?
Flibanserin
54
Which medical condition is MOST likely to cause ED?
a. HTN
b. Diabetes
c. Hypotension
d. Hyperlipidemia
b.
55
How do PDE5Is work to treat ED?
a. Increase test levels
b. Inhibit the breakdown of cGMP
c. Enhance dopamine release
e. Block adrenergic receptors
b.
56
Which of the following is an alternative treatment option for ED if PDE5Is are ineffective or CI?
a. SSRI
b. Tamsulosin
c. Alprostadil
d. Verapamil
c.
