Hemoperfusion is ineffectual in severe chloroquine poisoning

Objectives: To study the toxicokinetics in severe chloroquine poisoning, an d to evaluate the efficacy of hemoperfusion. Design:Case report on one observation. Setting: Medical intensive care unit (ICU) of the University Medical Center Utrecht, The Netherlands. Patient History: A previously healthy, 52-yr-old woman ingested 100 tablets containing 100 mg chloroguine base 1 hr before admission. At admission, sh e was drowsy, agitated, hypotensive, and in respiratory distress. Shortly t hereafter, she was resuscitated from cardiac arrest. After hemodynamic and respiratory stabilization, the patient was transferred to the medical ICU. Toxicokinetios Evaluation: During the course of her stay at the ICU, blood samples were taken for the determination of chloroquine and the metabolite desethylchloroquine concentration. Hemoperfusion was started 3.5 hrs after ingestion of the chloroquine tablets. Measurements and Main Results:The following toxicokinetics data during this severe chloroquine poisoning were calculated: apparent volume of the centr al compartment 181 L, apparent volume of distribution 1137 L., half-life in the distribution phase 6.4 hrs, half-life in the elimination phase 392.8 h rs, and total body clearance 2.01 L/hour, The average extraction ratio duri ng hemoperfusion was 0,07, 0.28, and 0,25, in plasma, erythrocytes and whol e blood, respectively. The total amount of chloroquine removed by hemoperfu sion was only 480 mg (5.3% of the amount ingested). Simulation of a hemoper fusion session over 5 hrs by using a column with an optimal extraction rati o of 1,0 would have removed 1,816 mg chloroquine, only 18.2% of the amount ingested. This limited contribution of hemoperfusion to the total clearance makes it ineffective. Conclusion: Hemoperfusion is not effective in severe chloroquine poisoning, even when started (relatively) early in the course of the intoxication. To xicokinetic evaluation of a chloroquine poisoning should be based on the ev aluation of plasma and whole blood concentrations.