Bunazosin in patients with impaired hepatic or renal function

Following a single oral dose of 6 mg bunazosin, a novel alpha 1-adrenoceptor antagonist, the pharmacokinetics and blood pressure behaviour of 37 patients were studied. 12 subjects had normal renal and hepatic function (mean creatinine clearance (GFR) 107 +/- 240 ml/min, antipyrine clearance (AP Cl) 47 +/- 10.2 ml/min; x +/- SD), 13 subjects had impaired renal function (mean GFR 38 +/- 11.5 ml/min, AP Cl 39 +/- 4.0 ml/min), and 12 patients had liver cirrhosis which was confirmed by liver biopsy (mean AP Cl 18 +/- 9.2 ml/min, GFR 92 +/- 8.1 ml/min). The groups studied were matched for age and body weight. The area under the plasma level time curve (AUC0-infinity) of bunazosin increased from 96.6 +/- 48.7 micrograms.ml-1.h in the normals to 157.0 +/- 101.0 micrograms.ml-1.h in the liver patients and to 298.2 +/- 199.4 micrograms.ml-1.h in patients with impaired renal function (P < 0.05). As there was a close correlation between plasma levels and antihypertensive activity of bunazosin in the present study, dosage adjustment of the alpha 1-receptor blocker in patients with impaired liver and kidney function appears to be mandatory.