This study is designed to investigate the comparison between alpha blocker monotherapy and 5-alpha-reductase inhibitor monotherapy following combination therapy in benign prostatic hyperplasia.

Inclusion Criteria:

1. Male aged 45 years old and above (with no upper limit of age)
2. patients who underwent combination therapy of alpha blocker and 5 ARI for more than 9 months
3. IPSS ≤ 12
4. Ability and willingness to correctly complete the micturition diary and questionnaire
5. Capable of understanding and having signed the informed consent form after full discussion of the research nature of the treatment and its risks and benefits

Exclusion Criteria:

1. An anticholinergic or antidiuretic if started less than 3 months prior to screening
2. Patients who had surgical treatment due to LUTS
3. Patients with suspected neurogenic bladder disorder
4. Patients with cancer of any type including cancer of the prostate or bladder
5. Patients with urethral stricture or bladder neck contracture
6. Patients with suspicious chronic prostatitis/chronic pelvic pain syndrome
7. Acute bacterial prostatitis less than 6 months prior to screening
8. Symptomatic acute urinary tract infection (UTI) less than 1 months prior to screening
9. Patients who had underwent prostatic biopsy less than one month prior to screening
10. Patients who had unstable angina or cerebral vascular disease less than 6 months prior to screening