A Review on Clinical Pharmacokinetics of Tamsulosin in Patients with Benign Prostatic Hyperplasia

Abstract

Context: Benign prostatic hyperplasia (BPH) that disturbs aged males is described as the abundant, chronic progressive disorder usually associated with lower urinary tract symptoms. The alpha 1A-adrenergic receptor antagonist, tamsulosin (Flomax®/Omnic®), seems to be an appropriate management from the view point of urological surgeons. The current review aimed to evaluate the clinical pharmacological properties of tamsulosin in prostate disorders. Evidence Acquisition: United States national library of medicine (PubMed, NLM) were searched from April 1991 to March 2016. The Mesh terms were: tamsulosin, tamsulosin pharmacokinetics in urology, tamsulosin in BPH and clinical pharmacokinetics of tamsulosin in BPH. Published clinical trials and review articles applicable to pharmacotherapy of tamsulosin in BPH were reviewed. Results: In patients with mild international prostate symptom score (< 8) to moderate symptoms of BPH, initial treatment with an alpha 1-adrenergic antagonist monotherapy were useful. With a half-life of 9 - 13 hours, the oral bioavailability of drug was reported 100%. The drug is metabolized by liver. Excretion through renal was reported 76%. Initial dose of drug was 0.4 mg/day and the maximum dose was reported 0.8 mg/day. The drug could cause dizziness, sever drowsiness and problems in thinking, driving and many other complications. Other serious adverse reactions could be mentioned as hives, rash, itching, and difficulty in breathing, swelling of face, lips, tongue and throat. Tamsulosin therapy should be stopped in patients who experience hypotension. Conclusions: To treat BPH therapeutically, it is necessary to stabilize severities of the patient’s symptoms with potential side effects of the treatment. Tamsulosin blocks alpha 1-receptors in smooth muscles both in the bladder neck and prostate, which leads to relaxation and subsequently less resistance to urinary flow. By advancement of tamsulosin, pharmacotherapy strategies could provide more appropriate guideline treatments; therefore, in Isfahan, Iran, innovative medical treatment for BPH was suggested based on both pharmacological and surgical clinical trials.