Drug dosage in end-stage renal disease (ESRD) patients undergoing haemodialysis. A predictive study based on a microcomputer program.

Drug dosage in end-stage renal disease (ESRD) patients undergoing haemodialysis is a very complex problem because of numerous variables relating to the patient, the type of drug administered and the type of dialysis and dialyser. We carried out a multifactorial study of these parameters using a microcomputer program written in BASIC. Three sets of data were fed into the computer: those relating to the biophysical characteristics of the patient, the type of dialysis and dialyser to be used, and others relating to the chemical and pharmacokinetic characteristics of the drug. From these, a predictive intravenous dosage regimen (bolus and infusion) was compiled for each ESRD patient. To check the program we used 2 drugs (tobramycin and vancomycin) and several types of dialyser. The findings were that, with tobramycin, an ESRD patient should be given different postdialytic doses, depending on the type of dialyser used. The maintenance doses calculated by the program were similar to those usually administered to patients receiving clinical treatment with this drug. In the case of vancomycin, the program calculated the clearance value in vivo through the 'Hemoflow F60' dialyser with a polysulphone membrane. The computer program calculated the maintenance dosage of vancomycin that should be given after each dialysis cycle so that its concentration did not fall below its minimum therapeutic concentration.