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Pseudocholinesterase deficiency
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Pseudocholinesterase deficiency

Pseudocholinesterase deficiency is a condition characterized by an increased sensitivity to certain medications used during general anesthesia, leading to prolonged muscle relaxation and breathing difficulties.

Overview

Pseudocholinesterase deficiency, also called butyrylcholinesterase deficiency, is a condition that causes an increased sensitivity to substances such as the medications succinylcholine and mivacurium. These drugs are typically used during general anesthesia to relax skeletal muscles, including those involved in breathing.

In individuals without this deficiency, these medications are metabolized within minutes. In affected individuals, the medications remain active longer than usual, meaning they may not be able to move or breathe on their own for several hours after administration. These patients require mechanical ventilation until the drugs are cleared from their system.

Symptoms

Affected individuals typically have no signs or symptoms until they have an abnormal reaction to specific substances. In addition to succinylcholine and mivacurium, they may have increased sensitivity to:

  • Cocaine
  • The local anesthetic procaine
  • Specific agricultural pesticides

Causes

Variants in the BCHE gene can cause this condition. This gene provides instructions for making the enzyme pseudocholinesterase (also known as butyrylcholinesterase), which is produced by the liver and circulates in the blood to metabolize these substances. Some variants cause the production of a non-functional enzyme, while others prevent its production entirely.

Some cases are acquired rather than inherited. These can be caused by factors such as pregnancy, increased age, chronic infections, kidney, liver, or heart disease, malnutrition, major burns, cancer, or certain prescription medications.

Inheritance

When caused by BCHE gene variants, the condition is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell must have a variant. Individuals with a variant in only one copy of the gene may take longer than usual to clear these substances from the body, but typically not as long as those with variants in both copies.

Frequently Asked Questions

In homozygous deficiency, the drug can last 4–6 hours or longer. The exact time varies with the degree of enzyme activity, but patients are usually kept intubated and mechanically ventilated until spontaneous breathing returns and neuromuscular monitoring shows adequate recovery.
void succinylcholine and mivacurium, which rely on pseudocholinesterase for breakdown. Instead, use non‑depolarizing agents such as rocuronium, vecuronium, or cisatracurium, which are metabolized by other pathways and have predictable durations.
blood test called the dibucaine number (or a quantitative pseudocholinesterase assay) measures enzyme activity. Low activity or a dibucaine number < 70 % suggests deficiency and should be reported to the anesthesiology team before any procedure.
Tell the anesthesiologist (or pre‑operative nurse) that you have a confirmed or suspected pseudocholinesterase deficiency. Provide any prior anesthesia records, the specific test results, and any medications or conditions (e.g., pregnancy, liver disease) that might further lower enzyme activity.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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