Lipid emulsion as a novel antidote

In the December issue of Emergency Medicine News James R. Roberts, MD began a series of articles on extreme toxicological emergencies and novel antidotes:

Occasionally, EMS can save someone in the field who has arrested or is about to, buying the EP some precious time. If the hapless individual simply needs naloxone, EMS has almost finished the resuscitation endeavor. Unfortunately, those who die outside the hospital from a drug overdose have essentially no chance of survival. And some toxins, such a colchicine, exotic hydrocarbons, or paraquat, can't be reversed by anyone on the planet.

This one was on lipid emulsions. The disclaimer:

There are also a few specific massive pharmaceutical overdoses, however, that are essentially a death sentence even when the patient arrives awake and talking. If one takes enough calcium channel blockers, beta blockers, or tricyclic antidepressants, the scene is often set for a lethal outcome once the bolus of toxin is swallowed, regardless of physician intervention.

This month's column begins a discussion of some novel antidotes that hold promise for reversing previously lethal overdoses. While the miraculous effects of naloxone and digifab are well referenced in the literature, the heroic antidotes described in my discussions lack scientific rigor, and are based mainly on theory and promising albeit scattered and anecdotal case reports. Nonetheless, the reputed antidotes appear to be helpful in otherwise desperate situations, and can be considered even when the specific offending pharmaceutical is unknown.

The use of lipid emulsion is generally accepted, though off label, for local anesthetic toxicity. Dr. Roberts discussed other uses including overdoses with TCAs, calcium blockers and beta blockers. There is limited experience with others and it can be considered when the offending drug is unknown. When to use it? The ideal circumstance would be in a patient deteriorating despite the use of conventional antidotal and supportive measures, but before they arrest. Much of the experience is as a last ditch measure in a patient already in arrest, and some dramatic results have been reported.

Two case registries exist and links are provided in the article.