Succinylcholine and Pseudocholinesterase

To the Editor.—  With the intensified use of organophosphorous insecticides by the general population and the increasing use of succinylcholine in general as well as in dental surgery, we would like to point out a problem that has come to our attention.Humans as well as other species have a specific acetylcholinesterase that is present at the cholinergic junctions of the nervous system and can be measured in red blood cells. In addition, pseudocholinesterase, a plasma enzyme, has no known physiological role but is essential for the rapid degradation of succinylcholine, a muscle relaxant. Levels of this enzyme can be depressed as a result of hepatocellular disease, or exposure to anticholinesterase agents such as the organophosphorous pesticides (Parathion, DDVP, Methylparathion, Demeton). A low plasma pseudocholinesterase level will increase sensitivity to succinylcholine, cause prolonged postoperative apnea, and may result in death from respiratory failure.Pseudocholinesterase catabolizes several drugs used in anesthesia