Effects of Doxazosin on Alpha 1-Adrenergic Receptors in Prostates with Benign Prostatic Hyperplasia

Objectives: The present study aimed to evaluate changes in mRNA and protein expression levels of α1-AR before and after doxazosin treatment. Methods: This 12-month, prospective study included males aged 50 or older who had lower urinary tract symptoms (LUTS) (International Prostate Symptom Score [IPSS] ≥ 8) with benign prostatic hyperplasia (BPH). All patients underwent transrectal ultrasound-guided prostate biopsy before and after doxazosin 4 mg medication for 12 months. The mRNA and protein expression of prostate α1-AR were analyzed using real-time quantitative reverse transcription-polymerase chain and Western blotting, respectively, before and after treatment. The clinical efficacy of doxazosin was evaluated according to changes in prostate volume, serum prostate-specific antigen (PSA) level, IPSS, quality of life (QoL) index, maximum flow rate, parameters in a voiding diary, and a Patient's Perception of Bladder Condition (PPBC) questionnaire. Results: Twenty patients aged 50-72 (median age 66) with LUTS secondary to BPH completed this study. Administering doxazosin for 12 months significantly increased α1-AR protein expression in the prostate. α1-AR mRNA expression did not change significantly after doxazosin administration. IPSS, QoL index, and PPBC scores significantly improved after 12 months of doxazosin treatment. Maximal flow rate, postvoid residual urine volume (PVR), prostate volume and the parameters from the voiding diary did not change significantly after 12 months. The change of IPSS total score and LUTS were maintained until 12 months after starting treatment with doxazosin. Conclusion: Doxazosin treatment was able to increase α1-AR protein expression in the prostate. Despite increased α1-AR expression, doxazosin provides sustained, significant relief of LUTS for up to one year without a decrease in efficacy.