BPH

Question 1

What are some medications that can aggravate the s/sx of BPH?

Answer 1

• Anticholinergics
• α1-adrenergic agonist
• Opioid analgesics
• Diuretics
• Testosterone

Question 2

What medications can be used to treat BPH? (4) (FAAP)

Answer 2

1. α-adrenergic antagonist (selective, non-selective)
2. 5α-reductase inhibitors (5ARIs)
3. Phosphodiesterase 5 inhibitor (PDE-5)
4. Anti-muscarinics

Question 3

MOA of α-adrenergic antagonists in Tx of BPH?

Answer 3

Antagonise α-1 adrenergic receptors → relax prostate SM → improve urine flow and s/sx

Question 4

Name the types of non-selective α-adrenergic antagonist (2)

What do they act on (ie why are they non-selective?)

Answer 4

Doxazosin, Terazosin

They antagonise both peripheral vascular and urinary α-1 adrenergic receptors

Question 5

ADEs of NON-SELECTIVE α-adrenergic antagonists?

How do we deal with this?

Answer 5

Risk of hypotension and syncope

Start low, titrate slowly to therapeutic dose

Question 6

Name the types of selective α-adrenergic antagonists (3)

What do they act on (ie why are they selective?)

Answer 6

Alfuzosin, Tamsulosin, Silodosin

They selectively antagonise α-1 adrenergic receptors in prostate and LUT

Question 7

Benefits that selective α-adrenergic antagonists have over non-selective α-adrenergic antagonists?

Answer 7

Lesser risk of hypotension → no need dose titration

Question 8

What are α-adrenergic antagonists used for (1) and NOT used for (3)?

Answer 8

Moderate-severe LUTS with small prostate (< 40g)

• Do not reduce prostate size
• Do not prevent progression of BPH/ need for surgery
• No effect on PSA

Question 9

General SEs of α-adrenergic antagonists?

Answer 9

Muscle weakness, fatigue, ejaculatory disturbance, headache

Question 10

ADEs of non-selective α-adrenergic antagonists?

What type of pts should we avoid this in?

Answer 10

Dizziness, first dose syncope, orthostatic hypotension

• Avoid in pts with Hx of syncope
• Avoid is monoTx in pts with BPH and HTN

Question 11

ADEs of selective α-adrenergic antagonists?

Especially Tamsulosin?

What type of pts should we avoid this in?

Answer 11

Ejaculatory disturbance (S > T > A)

Tamsulosin: Intraoperative Floppy Iris Syndrome (IFIS)
- Avoid initiation in men with planned cataract surgery until surgery is completed (or hold ≥14d before surgery)

Question 12

Onset of α-adrenergic antagonists?

Answer 12

Fast → days-weeks

Question 13

Name the 5ARIs (2)

Answer 13

Finasteride, Dutasteride

Question 14

MOA of 5ARIs?

Answer 14

Inhibits 5α reductase (Type II) → ↓ conversion from testosterone → DHT → ↓ size of prostate

Question 15

Advantages of 5ARIs? (4)

What must we do in regards to PSA levels?

Answer 15

• Slow progression of disease
• ↓ need for surgery
• ↓ PSA levels → consider adding if initial PSA > 1.5ng/mL
• Lesser risk of hypotension

Obtain PSA levels before initiation

Question 16

When do we use 5ARIs?

Answer 16

• Moderate-severe LUTS with large prostate (> 40g)
• For pts who want to avoid surgery/ cannot tolerate s/sx of α-1 antagonist

Question 17

Onset of 5ARIs?

Answer 17

Slow: 6-12 months

Question 18

ADEs of 5ARIs? (4)

Answer 18

• Ejaculatory disorders: ↓ semen during ejaculation/ delayed ejaculation
• ↓ libido (3-8%)
• ED (3-16%)
• Gynecomastia and breast tenderness (1%)

Question 19

Name the Phosphodiesterase 5 inhibitor (PDE5I) (1)

Answer 19

Tadalafil

Question 20

When is PDE5I used?

Answer 20

• Add-on Tx
• Especially for pts also with ED (helps with ED on top of BPH)

Question 21

Advantage (with regards to when to take the drug) (1) and disadvantages (2) of PDE5I?

Answer 21

Advantage:
- Take without regards to timing of sexual activity

Disadvantage:
- Does not reduce prostate size
- Does not improve urine flow rate

Question 22

Onset of PDE5I?

Answer 22

Days-weeks

Question 23

ADEs of PDE5I?

Answer 23

Significant hypotension

Question 24

Can PDE5I be used as monoTx?

Strength and dosing?

Answer 24

Yes.

Tadalafil 5mg OD.

Use for pts with younger age, lower BMI and higher baseline s/sx

Question 25

What are the 3 different combination Tx?

Answer 25

1. α-1 antagonist + 5ARI
2. 5ARI + PDE5i
3. α-1 antagonist + PDE5i

Question 26

In which pts would combination tx be effective?

Answer 26

Pts with moderate s/sx (ie IPSS 8-19, IPSS QoL 5-6) and prostate size > 25g

Question 27

Elaborate on α-1 antagonist + 5ARI

Answer 27

• For symptomatic pts with enlarged prostate
• Complement each other well → α-1 antagonist onset is weeks, while 5ARIs is months
• After 6 months, α-1 antagonist can be discontinued in moderate BPH

Question 28

Elaborate on 5ARI + PDE5i

Benefits? When should we NOT initiate PDE5i?

Answer 28

• Beneficial to mitigate sexual ADEs that arise from 5-ARIs/ concomitant ED
• Individuals with BPH and ED often have cardiac co-morbs → if unstable angina, do not initiate on PDE5i (contraindicated with nitrates)

Question 29

Elaborate on α-1 antagonist + PDE5i

Do we choose the nonselective or uroselective α-1 antagonist?

What must we take note about the dosing?

Does it help to reduce prostate size?

Answer 29

• Only use uroselective α-1 antagonist (use with nonselective α-1 antagonist → severe life-threatening hypotension)
• Must optimise/ stabilise α-1 antagonist dose first before adding PDE5i + use lowest effective dose of PDE5i
• Does not help to reduce prostate size

Question 30

Name the most commonly used anti-muscarinic

Answer 30

Oxybutynin

Question 31

MOA of anti-muscarinics?

When are anti-muscarinics used?

What must you take note of PVR?

Answer 31

MOA: block muscarinic receptor in detrusor muscle → ↓ involuntary contraction of bladder

For pts with irritative voiding s/sx (overactive bladder) → helps them pee less

ONLY use if PVR < 250ml (or 150ml better)

Question 32

Non-pharmacological Tx for BPH?

Answer 32

• Limit fluid intake in evening
• Minimise caffeine and alcohol intake
• Educate pt to take their time to empty bladder completely and often
• Avoid medications that exacerbate s/sx