Pharmacokinetics of tamsulosin in subjects with normal and varying degrees of impaired renal function: an open-label single-dose and multiple-dose study.

OBJECTIVE: This study was performed to estimate whether the pharmacokinetics and safety of tamsulosin, and alpha(1A)-adrenoceptor antagonist for the treatment of symptomatic benign prostatic hyperplasia (BPH), are influenced by impaired renal function.
METHODS: In an open-label study design, the plasma concentration profile of 0.4 mg tamsulosin p.o. was studied in age-matched groups of male subjects with normal (n = 10), moderately impaired (n = 10), and severely impaired (n = 8) renal function after single-dose administration and in steady state, i.e. after 21 days of multiple-dose administration.
RESULTS: The AUC of total, but not of unbound, tamsulosin was correlated to creatinine clearance and alpha(1)-acid glycoprotein plasma levels, and was found to be significantly higher in both groups of subjects with impaired renal function than in controls after single- and multiple-dose administration. However, the pharmacokinetics of total and unbound tamsulosin were comparable for both trail periods.
CONCLUSIONS: Impaired renal function increases total tamsulosin plasma concentration by approximately 100% after single-dose administration and in steady state. Since active unbound drug levels are not affected, no dose modification is required in symptomatic BPH patients with renal impairment.