• Mean maximal change of the standing systolic blood pressure (SBP) from half hour prior to till six hour after administration of the drug (baseline) with vardenafil administration versus placebo [ Time Frame: From half hour prior to till six hour after administration of the drug (baseline) ]
  

• Mean maximal post-baseline change of the standing and supine diastolic blood pressure (DBP) [ Time Frame: From half hour prior to till six hour after administration of the drug (baseline) ]
  
• Mean maximal post-baseline change supine SBP, and (3) the pattern of changes of the SBP and DBP from half hour prior to till six hours after administration of the drug [ Time Frame: From half hour prior to till six hour after administration of the drug (baseline) ]
  

Inclusion Criteria:

• Age between 50 to 80 years old

• Clinically diagnosed to have lower urinary tract symptoms secondary to BPH:

  1. Suffered from lower urinary tract symptoms with International Prostate Symptom Score (IPSS) >=8
  2. Detectable prostatic enlargement determined by Digital Rectum Examination (DRE)
  3. Urinary flow between 5 to 15ml/second in a total void volume >=150mL
• Currently on regular doxazosin GITS once-daily for at least 4 weeks without clinically significant side effects
• Complaints of erectile dysfunction with Erectile Function domain (EF) of the International Index of Erectile Function (IIEF) score <= 21

Exclusion Criteria:

• Congestive heart failure, unstable angina, arrhythmia, myocardial infraction
• Hypertension or on any antihypertensive agents
• Take nitrate and medication contradicted to vardenafil
• Uncontrolled or poorly controlled diabetes mellitus
• Intolerance or contra-indicated for the use of vardenafil
• Hepatic disorder