Pharmacokinetics and pharmacodynamics of clonidine in varying states of renal function

Previous studies have reported a therapeutic window of 0.8 to 2.0 ng/ml within which clonidine exerts its antihypertensive effect. This study was designed to investigate whether there was any loss of blood pressure control when plasma clonidine concentrations exceeded this window owing to its accumulation in renal insufficiency. The results indicate that clonidine concentrations of up to 30 ng/ml in patients with end-stage renal disease (ESRD) can be associated with a maintenance of blood pressure control. It remains to be learned whether this phenomenon of high concentrations and control of blood pressure in our ESRD patient population may be related to altered (decreased) peripheral alpha-receptor sensitivity and inability to develop vasoconstriction. There is precedence for autonomic imbalance and altered tissue sensitivity in ESRD.