Intravenous Lipid Emulsion to Reverse Acute Drug Toxicity in Pediatric Patients

During the past decade intravenouslipid emulsions, routinely used for nutritional support, have been increas-ingly studied as antidotes to reverse acute, life-threatening drug toxicity.1-3 Their use has been directed to drug toxi-city from therapeutic complications of local anesthetics and acute poisonings from other medications. The observation that lipid emulsions could sequester a lipid-soluble drug was reported in 1962 with a reduction of thiopental anesthetic duration in rats4 and was described in 1974 in in vitro and in vivo studies with chlorpromazine and rabbit blood.5 A search for better therapy for acute bupi-vacaine toxicity led to experiments in 1998 in rats in which the intravenous in-fusion of a commercially available lipid emulsion (Intralipid, Fresenius Kabi AB, Sweden) improved recovery from bupi-vacaine-induced cardiotoxicity.6 Several other animal experiments followed,1,2 and the first human cases reported to use intravenous lipid emulsions as a rescue or antidotal therapy for acute drug toxici-ty were published in 2006.1 Several mechanisms by which an in-travenous lipid emulsion may exert its anti dotal action on lipid-soluble drugs have been pro posed.7 A commonly cit-ed mechanism involves the creation of a “lipid sink ” for lipid-soluble drugs by the lipid emulsion. In this theory, the infusion of a lipid emulsion creates a distinct lipid com-partment within the bloodstream, which “traps ” lipophilic compounds, making them less available to tissues and thereby reducing toxicity. Another theory focuses on the augmentation of cardiac energy sources. Local anesthetics are known to interrupt the transport of fatty acids into the cardiac mitochondria, which reduces energy supplies. A lipid emulsion may act to supply substrate to provide an energy source that is sufficient to restore normal cardia