4-methylpyrazole monitoring during haemodialysis of ethylene glycol intoxicated patients.

4-methylpyrazole (4-MP) was administered IV during haemodialysis of two ethylene glycol-intoxicated patients with anuric renal failure. The plasma 4-MP concentration decreased after each pass through the dialyser, indicating its dialysability in humans. In these two cases, the extraction coefficient was 0.78 and 0.71, and the mean dialysance was calculated to be 137 and 117 ml.min-1, corresponding to a 4-MP removal rate of 83 and 50 mg.h-1, respectively. The results imply that a higher rate of 4-MP infusion would be needed to replace 4-MP lost due to metabolism and to haemodialysis. The treatment of two ethylene glycol poisoned patients who were haemodialysed raised the problem of the dialysance of 4-MP. A recent study in pigs indicated that the amount of 4-MP removed by haemodialysis was significant [8]. No data were available for man. The aim of the study was to evaluate the dialysability of 4-MP in the two intoxicated patients, and to estimate how to compensate for 4-MP elimination during haemodialysis.