Pseudocholinesterase deficiency

Pseudocholinesterase deficiency is an inherited blood plasma enzyme abnormality. People who have this abnormality may be sensitive to certain anesthetic drugs, including the muscle relaxants succinylcholine and mivacurium as well as other ester local anesthetics. These drugs are normally metabolized by the pseudocholinesterase enzyme.

When anesthetists administer standard doses of these drugs to a person with pseudocholinesterase deficiency, the patient experiences prolonged paralysis of the respiratory muscles, requiring an extended period of time during which the patient must be mechanically ventilated. Eventually the muscle-paralyzing effects of these drugs will wear off despite the deficiency of the pseudocholinesterase enzyme. If the patient is maintained on a mechanical respirator until normal breathing function returns, there is little risk of harm to the patient. This enzyme abnormality is a benign condition unless a person with pseudocholinesterase deficiency is exposed to the offending pharmacological agents.