DISPOSITION OF ALFENTANIL IN BURNS PATIENTS

We have studied the disposition of alfentanil in six patients(who had suffered 10–30% surface area burns 5–21days previously) undergoing surgical debridement and graftingand compared the data with those from a control group of sixpatients matched for age, sex and weight undergoing body surfacesurgery of similar duration. Plasma samples were collected upto 480 min after an i. v. bolus of alfentanil 50 fig kg^–1.Drug concentrations were measured by radioimmunoassay and alfentanilbinding to plasma proteins by equilibrium dialysis. The burnspatients had significantly greater concentrations of alpha-1-acidglycoprotein (AAG) and smaller concentrations of albumin. Themean protein binding of alfentanil was 94.2 (SEM 0.05)% in theburns group and 90.7 (0.4)% in the control group (P = 0.004).There was a good correlation between AAG concentration and proteinbinding (r= 0.8). The volume of distribution and total clearanceof alfentanil were reduced significantly in the burns group.The clearance of the raction and the elimination half-life ofalfentanil were not decreased significantly. (Br. J. Anaesth.1992; 69: 447–450) ^*Present address: Department of Anaesthesia, Western Infirmary,Dumbarton Road, Glasgow Gil 6NT.