Plasma protein binding of thiopental in patients with impaired renal or hepatic function.

Binding of thiopental to proteins in plasma from healthy, cirrhotic, and uremic subjects was studied using equilibrium dialysis. In plasma from healthy volunteers 28.0 plus or minus 0.9 per cent of thiopental was unbound. In plasma from patients with hepatic disease 53.0 plus or minus 2.1 per cent was unbound, while in patients with renal disease 55.7 plus or minus 1.5 per cent remained unbound. The decreased binding in uremia could not be explained completely by competitive displacement by nitrogenous end products or by hypoalbuminemia, although hypoalbuminemia may account for the decreased binding in cirrhotic patients.