Table 1: Agents used in the treatment of BPH (1)

Risks of treatment may outweigh benefits

• Mild symptoms (IPSS/AUA-SI score < 7) or moderate-to-severe symptoms (IPSS/AUA-SI score ≥8)

• Not bothered by their symptoms

• Not experiencing complications of BPH

Re-examine annually.

Selective short-acting alpha-1 blockers prazosin (Hypovase), alfuzosin (Xatral), indoramin (Doralese)

Selective long-acting alpha-1 blockers terazosin (Hytrin), doxazosin (Cardura, Carsem XL, Doxane XL), slow-release (SR) alfuzosin (Alfu, Tevax, Xatger, Xatral)

Partially subtype (alpha-1a)–selective agents

Tamsulosin (Omnexel, Omsil, Prolosin, Tamnexyl XI, Tamnic, Tamsu), silodosin (Urorec)

• A significant component of LUTS secondary to BPH is related to the smooth-muscle tension in the prostate stroma, urethra, and bladder neck, and mediated by the alpha-1-adrenergic receptors.

• The 3 subtypes of the alpha-1 receptor include 1a, 1b, and 1c. As the alpha-1a receptor is most specifically concentrated in the bladder neck and prostate, drugs that are selective for this receptor (ie, tamsulosin, silodosin) may have a potential therapeutic advantage.

• The efficacy of the older alpha-blockers doxazosin and terazosin (Hytrin) is dose-dependent; however, the higher the dose, the more likely the adverse events (orthostatic hypotension, dizziness, fatigue, ejaculatory disorder, nasal congestion).

• Despite the requirement for dose titration and BP monitoring, older alpha-blockers doxazosin and terazosin (Hytrin), often less costly, appear to be equally effective to tamsulosin and alfuzosin, and the 2010 AUA guidelines recommend them as reasonable choices for patients with moderate-to-severe LUTS due to BPH.

• Alpha-blockers use is expected to result in approximately 4- to 6-point improvement in IPSS/AUA-SI scores.

• Alpha-blockers have not been shown to reduce the overall long-term risk for acute urinary retention (AUR) or BPH-related surgery.

• Ask patients about planned cataract surgery; alpha-blockers should not be initiated until this is completed.

• Phenoxybenzamine is non-selective, antagonising both the alpha 1- and alpha 2-adrenergic receptors, which results in a higher incidence of adverse effects.

• AUA guideline for BPH retains the statement that insufficient data exist for a recommendation of phenoxybenzamine or of prazosin for treatment of LUTS secondary to BPH.

• Phosphdiesterase-5 (PDE5) inhibitors mediate smooth muscle relaxation in the lower urinary tract.

• Statistically significant symptomatic improvements have been reported for patients with BPH receiving tadalafil, which has now been approved for the treatment of BPH (5mg dose only).

• Inhibition of 5-alpha-reductase type 2 blocks the conversion of testosterone to more potent dihydrotestosterone (DHT), resulting in the inhibition of prostatic growth, apoptosis, and involution.

• 5-alpha-reductase inhibitors are believed to be appropriate and effective treatment in patients with LUTS and enlarged prostates.

• 5-alpha-reductase inhibitors improve LUTS by decreasing prostate volumes; thus, patients with larger prostates may achieve a greater benefit.

• Maximal reduction in prostate volume requires 6 months of therapy.

• Both finasteride and dutasteride actively reduce DHT levels by more than 80%, improve symptoms, reduce the incidence of urinary retention, and decrease the likelihood of surgery for BPH.

• Adverse effects are primarily sexual in nature (decreased libido, erectile dysfunction, ejaculation disorder).

• Both finasteride and dutasteride may reduce PSA values by as much as 50%.

• Data from 2 large, randomised, controlled trials observed an increased risk of being diagnosed with a more serious form of prostate cancer, though a decreased incidence of prostate cancer overall was also observed.

• Appropriate evaluations to rule out other urological conditions that might mimic BPH, including prostate cancer, are therefore recommended.

• The MTOPS trial showed that combination therapy with finasteride and doxazosin reduces the risk of progression with greater improvement in IPSS than therapy with finasteride or doxazosin alone.

• The risks of AUR and BPH-related surgery were reduced with combination therapy or finasteride in comparison with doxazosin monotherapy.

• The 2010 AUA BPH guidelines recommend anticholinergic agents for management of LUTS in patients who do not have an elevated PVR and whose LUTS are primarily irritative (due to concerns of urinary retention associated with anticholinergics).

• Assess baseline PVR prior to initiation of anticholinergic therapy, to assess for urinary retention.

• Caution recommended if PVR >250-300ml.