BPH

Question 1

Classifications of the severity of urinary retention according to the international prostate symptom score? Do we treat symptoms?

Answer 1

• Mild: 0-7. Consider watch and wait
• Moderate: 8 - 19. Consider AAB
• Severe: 20 - 35. Refer to urology

Question 2

Labs to be done in a patient with suspected BPH?

Answer 2

• Urinanalysis
• Prostate specific antigen (PSA) to determine if 5-ARI is to be done

Question 3

Non-pharmacotherapy for BPH?

Answer 3

• Reduce caffeine and alcohol
• Avoid excessive fluid intake at night
• Treat constipation if present (constipation due to pressure on rectum caused by enlarged prostate)
• Modify medications (e.g. change timing of diuretics)

Question 4

Significant side effects of Alpha-1 adrenergic receptor blockers (AAB)?

Answer 4

Intraoperative floppy iris syndrome during cataract surgery

Question 5

List the AABs and their dosing regimen

Answer 5

• Alfuzosin XL 10 mg ON after meal
• Tamsulosin 0.4-0.8 mg after meal
• Tamsulosin CR 0.4 mg after meal
• Doxazosin 1-8 mg ON
• Doxazosin XL 4-8mg OD with meals (titrate upon week 4 if still have symptoms)
• Terazosin 1-20 mg ON

Question 6

Why is AAB dosed at night?

Answer 6

Hypotension which may cause dizziness throughout the day if taken in the morning

Question 7

Alternate classes of medications used in BPH

Answer 7

• Beta-3 adrenergic agonists: promote relaxation without bladder contractility (e.g. mirabegron 25 - 50mg OD)
• Anticholinergics: for over-reactive bladder (OAB) but no increased post-void residual (e.g. solifenacin 5 mg OD, oxybutynin ER 5-10 mg OD, Tolterodine)

Question 8

Class of drugs used to prevent progression of BPH?

Answer 8

5-alpha reductase inhibitors (5-ARI)

Question 9

Mechanisms of 5-ARIs

Answer 9

Block conversion of testosterone to dihydrotestosterone (DHT)

Question 9

Side effects of 5-ARIs

Answer 9

1. Suppression of PSA (hence must check baseline before initiation of 5-ARI)
2. Sexual dysfunction

Question 10

Give two examples of 5-ARIs and their dosing

Answer 10

1. Finasteride 5 mg OD
2. Dutasteride 0.5 mg OD

Question 11

When should a combination of AAB and 5-ARI be used?

Answer 11

Prostate enlargement with moderate to severe symptoms of BPH (IPSS > 12)