Benign Prostatic Hyperplasia
Dutasteride is used to reduce prostatic size, urinary obstruction and associated manifestations (e.g., urinary hesitancy and/or urgency, nocturia), the risk of acute urinary retention, and the risk of the need for surgery in patients with symptomatic benign prostatic hyperplasia (BPH, benign prostatic hypertrophy).
Benign prostatic hyperplasia, a noncancerous abnormal enlargement of the prostate gland that occurs in most men older than 50 years of age, produces lower urinary tract symptoms such as a weak urinary stream, difficulty in initiating urination, urinary frequency and urgency, and nocturia. Urinary flow obstruction secondary to BPH generally is treated with surgical correction of the hyperplasia (e.g., transurethral resection of the prostate [TURP], transurethral incision of the prostate [TUIP], open prostatectomy) or other procedures (e.g., transurethral microwave thermotherapy [TUMT], transurethral needle ablation [TUNA]) in patients who fail medical treatment or catheter removal or in those who have refractory urinary retention, recurrent urinary tract infections, persistent hematuria, bladder stones, or renal insufficiency. However, medical therapy with steroid 5α-reductase inhibitors (e.g., dutasteride, finasteride), which shrink the prostate gland, and/or other drugs (e.g., α1-adrenergic blocking agents such as alfuzosin, doxazosin, tamsulosin, or terazosin), which reduce symptoms, may be a useful alternative to surgery in patients with obstructive manifestations who are unwilling to undergo surgical correction of BPH. Medical therapy may aid those who may be at increased risk from, but not necessarily candidates for, prostate surgery.
Pooled data from a number of placebo-controlled clinical trials evaluating dutasteride (0.5 mg daily) in patients with BPH indicate that treatment with the drug reduces prostate volume and obstructive manifestations (e.g., interrupted or weak stream, sensation of incomplete bladder emptying or straining, urinary urgency and/or frequency, nocturia), reduces the incidence of acute urinary retention and the need for surgery, and increases maximum urinary flow. Therapy with dutasteride in patients with BPH appears to prevent the progression of the disease.
Dutasteride is used in combination with tamsulosin for the treatment of symptomatic BPH. In a long-term (mean follow-up: 4 years), multicenter, randomized, double-blind, parallel-group study (Combination of Avodart and Tamsulosin [CombAT]) in men 50 years of age or older with moderate to severe BPH and prostate enlargement, interim analysis showed that combined therapy with dutasteride (0.5 mg daily) and tamsulosin (0.4 mg daily) was more effective than either drug alone in relieving lower urinary tract symptoms; a difference in symptom control was apparent within 9 months and persisted following 4 years of treatment. However, following 4 years of treatment, combined therapy with dutasteride and tamsulosin provided no additional benefit over dutasteride alone in reducing the incidence of acute urinary retention or the need for BPH-related surgery. In addition, although combined therapy was more effective than either drug alone in improving maximum urinary flow at 2 years, the difference between combined therapy and dutasteride alone was no longer significant after 4 years of treatment.
Most experts state that combined therapy with a 5α-reductase inhibitor and an α1-adrenergic blocker may be considered for men with symptomatic moderate to severe BPH and demonstrable prostate enlargement. Men at risk for BPH progression are most likely to benefit from combined therapy. Studies show that combined therapy with a 5α-reductase inhibitor and an α1-blocker is more effective than therapy with either drug alone in preventing long-term BPH symptom progression.
For further information on the use of 5α-reductase inhibitors in the management of BPH,