BPH & ED Flashcards

1
Q

How is dihydrotestosterone (DHT) formed and what does it do?

A

Testosterone converted to DHT by 5 alpha reductase in prostate

DHT: normal growth / enlargement of prostate

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2
Q

What is the prostate made up of?

A
  • epithelial tissue (growth stimulated by androgens)
  • stromal tissues innervated by alpha1 adrenergic receptors
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3
Q

Pathophysiology of BPH (short term)?

A

Static component
- testosterone converted to DHT -> prostate enlarges

Dynamic component
- increase smooth muscle tissue & agonism of alpha1 receptors -> narrowing of urethra outlet

=> urethral obstruction, s&sx

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4
Q

Pathophysiology of BPH (long term)?

A
  • early phase: bladder muscle force urine thru narrowed urethra by contracting more forcefully
  • over time, bladder (detrusor) muscle becomes thicker (hypertrophy)
  • detrusor muscle becomes irritable +/ overly sensitive (detrusor overactivity / instability) -> contract abnormally in response to small amt of urine in bladder
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5
Q

What is LUTS and what does it consist of?

A

Lower urinary tract sx
- obstructive sx (early stage): hesitancy, weak stream, sensation of incomplete emptying, dribbling, straining, intermittent flow
- irritative sx (late stage If untreated): dysuria, frequency, nocturia, urgency, UI

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6
Q

Complications of BPH?

A
  • recurent UTI
  • bladder stones
  • acute urinary retention
  • UI
  • hematuria
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7
Q

What score is used for BPH and what is the score & sx for:
- mild
- moderate
- severe

A

AUA-SI score
- mild ≤7: asymptomatic / mildly sx
- moderate 8-19: the above + obstructive & irritative voiding sx
- severe ≥20: the above + ≥1 complications of BPH

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8
Q

What is the prostate specific antigen (PSA) for BPH?

A

> 1.5ng/mL

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9
Q

What postvoid residual is considered inadequate emptying? What is normal?

A

> 200 mL
(normal <100mL)

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10
Q

What medications contribute to BPH? Why?

A
  • anticholinergics (decrease bladder contractility)
  • alpha1 adrenergic agonist (contract prostate smooth muscle)
  • opioid (increase urinary retention)
  • diuretics (increase urinary frequency)
  • testosterone (stimulate prostate growth)
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11
Q

When should treatment be started for BPH? When can watchful waiting be considered?

A

Start: if sx bother pt / complications

Watchful waiting: mild, or moderate-severe with no bothering sx

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12
Q

Nonpharm for BPH? (5)

A
  • limit fluid intake in the evening
  • minimise caffeine & alcohol intake
  • take time to empty bladder completely & often
  • avoid meds that worsen sx
  • transurethral resection of prostate (for complications)
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13
Q

What pharm options are used for BPH obstructive sx?

A
  • alpha1 adrenergic antagonist
  • 5 alpha reductase inhibitors
  • PDE5 inhibitors (only tadalafil)
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14
Q

What are selective and nonselective alpha1 antagonists?

A
  • selective: alfuzosin, tamsulosin, silodosin
  • nonselective: terazosin, prazosin, doxazosin
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15
Q

Are selective or nonselective alpha1 antagonists preferred for BPH? When should the non-preferred one be used?

A

preferred: selective

nonselective preferred if pt has BPH + HTN (but cannot use as monotherapy)

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16
Q

What are the following indicated for BPH:
- alpha1 antagonist
- 5 alpha reductase inhibitor
- PDE5 inhibitor

A
  • alpha1 antagonist: moderate-severe LUTS with small prostate (<40g)
  • 5 alpha reductase inhibitor: moderate-severe LUTS with large prostate (>40g), if PSA >1.5ng/mL
  • PDE5 inhibitor: add-on for pts with BPH-LUTS +- ED
17
Q

Which meds for BPH can decrease prostate size?

A

5 alpha reductase inhibitor

18
Q

Examples of 5 alpha reductase inhibitors?

A

Finasteride, dutasteride

19
Q

SE of alpha1 antagonist?

A
  • hypotension (nonselective > selective) & related SE
  • HA (dilation of brain vessels)
  • ejaculatory disturbance (delayed / retrograde)
  • intraoperative floppy iris syndrome (for tamsulosin) -> complicates cataract surgery
20
Q

What should pts with cataract surgery do if they plan to start tamsulosin? What are they trying to avoid?

A

Avoid intraoperative floppy iris syndrome

avoid initiation until surgery has been completed, or hold 2-3w before surgery

21
Q

What do the selective alpha adrenergic receptors target?

A

urinary alpha1 adrenergic receptors in prostate, prostatic urethra, bladder neck

22
Q

Do the following have fast or slow onset:
- alpha1 antagonist
- 5 alpha reductase inhibitor
- PDE5 inhibitor

A
  • alpha1 antagonist: fast
  • 5 alpha reductase inhibitor: slow (6-12m)
  • PDE5 inhibitor: fast
23
Q

SE of 5 alpha reductase inhibitor?

A
  • ejaculatory disturbance, less libido, ED
  • gynecomastia
24
Q

Which pts will benefit from combi therapy of BPH meds? What combi should be used for what indication?

A

Benefits pts with moderate sx & prostate >25g

  • alpha1 antagonist + 5ARI: sx pts with enlarged prostate (most common)
  • 5ARI + PDE5i: pts with ED or experience ED from 5ARI use
  • alpha1 antagonist + PDE5i: rarely used due to hypotension
25
Q

What pharm option can be used for irritative BPH sx? When is it indicated?

A
  • antimuscarinics (oxybutynin, tolterodine, solifenacin)
  • indicated for pts with irritative sx & PVR <250mL
26
Q

What is considered ED?

A

persistent (≥6m) inability to achieve or maintain erection of sufficient duration & firmness to complete satisfactory intercourse

27
Q

How do PDE5 inhibitors work?

A

Inhibit PDE5 enzymes -> more cGMP -> smooth muscle relaxation & vasodilation -> erection

Only after sexual stimulation

28
Q

Examples of PDE5 inhibitors?

A

sildenafil, vardenafil, tadalafil, avanafil

29
Q

When and how (food) should the PDE5 inhibitors be taken?

A
  • sildenafil: 1h before sex, empty stomach
  • vardenafil: 1h before sex, empty stomach
  • tadalafil: up to 36h before sex, regardless of food
  • avanafil: 30min before sex, regardless of food
30
Q

Major interactions with PDE5 inhibitors?

A
  • CYP3A4 inhibitors -> increase serum conc of PDE5i
  • nitrates -> life threatening hypotension
31
Q

How long to space nitrates from PDE5i?

A
  • avanafil: 12h after
  • sildenafil, vardenafil: 24h after
  • tadalafil: 48h after
32
Q

SE of PDE5i?

A
  • hypotension (dizzy)
  • HA, flushing, rhinitis (vasodilation)
  • muscle & back pain (tadalafil due to PDE 11 affinity)
  • QTc prolongation (vardenafil)
  • photosensitivity, colour discrimination (sildenafil & vardenafil due to PDE6 in retina)
  • prolonged erections & priapisms (go A&E if >4h)
33
Q

What can be used for ED?

A
  • PDE5 inhibitors
  • testosterone (for sx hypogonadism)
  • alprostadil
34
Q

When should testosterone be discontinued for ED?

A

if no improvement of ED sx after 3m

35
Q

Do PDE5 inhibitors and alprostadil require sexual stimulation to work?

A

PDE5i yes, alprostadil no