This is an open-label, single-arm, prospective interventional study to assess the tolerability and efficacy of Harnalidge® OCAS® 0.4 mg in Taiwan patients who are unsatisfied with tamsulosin 0.2 mg for the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).

After obtaining informed consent, subjects who meet the inclusion criteria and not violating the exclusion criteria will be enrolled to receive Harnalidge® OCAS® 0.4 mg for treatment. The interventional period for the study is three months after the first date of enrollment or until the patients are discontinued the treatment of Harnalidge® OCAS®. All subjects will be instructed to contact the site if a patient's partner becomes pregnant during or within 90 days from the discontinuation of dosing, the investigator should report the information to the sponsor as if it is an SAE.

Inclusion Criteria:

• Diagnosed as LUTS associated with BPH
• Currently taking oral tamsulosin 0.2 mg for at least 4 weeks
• Unsatisfied with the treatment of tamsulosin 0.2 mg The definition of 'unsatisfaction' is based on patient's satisfaction. Investigator will ask patient one question "Are you satisfied with your current treatment?" prior to study enrollment
• IPSS-QOL score ≧3 points at baseline

Exclusion Criteria:

• Subjects who underwent prostatectomy during the period of one year prior to this study
• Subjects with neurogenic bladder dysfunction, bladder neck sclerosis, urethral stricture, prostatic cancer, cystolithiasis, severe vesical diverticulum, urinary tract infection
• Subjects with any other complication which may cause voiding dysfunction
• Subjects with severe hepatic dysfunction, severe renal dysfunction, severe cardiovascular disorders, orthostatic hypotension, or senile dementia
• Subjects clinically significant condition, which in the opinion of the investigator makes the patients unsuitable for the trial
• Subjects who are currently participating in any other investigational drug study or who have participated in a study of an investigational drug within 3 months prior to this study