Due to the increased skin penetration and good local anesthetic effects of EMLA cream, it is used as a local anesthetic to reduce the pain caused by venipuncture in hemodialysis patients. The active ingredients of EMLA cream, lidocaine and propitocaine, are transferred to the blood after the application of the cream under an occlusive dressing for 1 hour. Information about drug elimination during hemodialysis is important. However, there is no information about the hemodialysis efficiency of lidocaine and propitocaine during hemodialysis performed using high-performance dialysis membranes. Therefore, the clearance of lidocaine and propitocaine during hemodialysis were evaluated using miniaturized in vitro dialysis systems. Twenty-ml samples of human plasma containing lidocaine and propitocaine were dialyzed for 240 min using the miniaturized dialyzers (effective surface area, 26.4 cm2 plasma flow, 2mL/min;dialysate flow, 5mL/min), which were composed of hollow fiber dialysis membranes that had been removed from a commercially available hemodialyzer, and the lidocaine and propitocaine concentrations of the plasma samples were measured. The plasma concentrations of lidocaine and propitocaine gradually decreased due to dialysis. The clearance values of lidocaine and propitocaine during hemodialysis conducted in clinical conditions (effective surface area, 1.5 m2 blood flow, 200mL/min;dialysate flow, 500mL/min;hematocrit;44%) were predicted to be 34.2 and 64.1 mL/min, respectively. The predicted clinical hemodialysis clearance values were lower than the total body clearance values (lidocaine, 950 mL/min; propitocaine, 1910 to 2570 mL/min).
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