Abstract
We report a case of an organophosphate poisoned patient in whom pralidoxime (2-PAM) pharmacokinetics and clearance during continuous venovenous hemodialysis (CVVHD) were assessed. A 67-yr-old male weighing 45kg, who had been undergoing regular hemodialysis therapy for 3 years, ingested 15ml of 47% parathion in an attempt to commit suicide. After successful cardiopulmonary resuscitation using atropine 48.5mg and 2-PAM 2.0g, the patient was admitted to the ICU. He received a continuous infusion of 2-PAM at 0.1g·hr-1 for 20hrs under CVVHD, and blood and hemodialysis fliud samples were collected to calculate clearance. Then 1.0g of 2-PAM was infused over 30min and blood samples were collected to calculate pharmacokinetic parameters. Blood 2-PAM concentration during the continuous infusion was around 22-23mg·ml-1, much higher than the “therapeutic level” of 4mg·ml-1. The calculated clearance by CVVHD was about 8ml·min-1. The calculated half-life of the elimination phase was 40hrs, which was much greater than the usually expected (1.1hr). The calculated total clearance was 4.5l·hr-1, which was less than 1/10 of that in healthy volunteers. These results indicate that we have to be very cautious in administering 2-PAM to patients requiring CVVHD.
