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Neuroleptic Malignant Syndrome

By

David Tanen

, MD, David Geffen School of Medicine at UCLA

Last full review/revision Feb 2021| Content last modified Feb 2021
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Topic Resources

Neuroleptic malignant syndrome is confusion or unresponsiveness, muscle rigidity, high body temperature, and other symptoms that occur when certain antipsychotic (neuroleptic) drugs or anti-vomiting (antiemetic) drugs are used.

  • Neuroleptic malignant syndrome develops in a very small number of people who are given certain types of drugs.

  • Symptoms include a dangerously high body temperature, muscle rigidity, and agitation.

  • Doctors base the diagnosis on the person's symptoms and on what they find during a physical examination.

  • Treatment involves stopping the drug, reducing body temperature, and providing support in an intensive care unit.

Neuroleptic malignant syndrome develops in a small number of people who are treated with antipsychotic or antiemetic drugs (see table Drugs That Can Cause Neuroleptic Malignant Syndrome Drugs That Can Cause Neuroleptic Malignant Syndrome Neuroleptic malignant syndrome is confusion or unresponsiveness, muscle rigidity, high body temperature, and other symptoms that occur when certain antipsychotic (neuroleptic) drugs or anti-vomiting... read more ), usually within the first few weeks of treatment. The risk of developing the syndrome varies between 0.02% and 3% depending on many factors. The syndrome is most common among men who, because they are agitated, are given rapidly increased doses of antipsychotics or high doses initially. Doctors are not sure why the syndrome develops.

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Symptoms of Neuroleptic Malignant Syndrome

Symptoms usually develop over a few days and include

  • Confusion, agitation, or coma

  • Muscle rigidity

  • A high temperature, often over 104° F (40° C)

  • A fast heart rate

  • A fast breathing rate

  • High or variable (labile) blood pressure

Diagnosis of Neuroleptic Malignant Syndrome

  • Typical symptoms developing in a person who is taking a drug known to cause neuroleptic malignant syndrome

Doctors suspect neuroleptic malignant syndrome when people taking a drug known to cause neuroleptic malignant syndrome develop characteristic symptoms and physical examination findings, particularly severe muscle rigidity. There are no tests that confirm the diagnosis. However, because other disorders (for example, meningitis Introduction to Meningitis Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space). Meningitis can be... read more and sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more ) can cause similar symptoms, doctors often do tests for those disorders. Doctors also do blood and urine tests to look for muscle protein breakdown and kidney injury.

Treatment of Neuroleptic Malignant Syndrome

  • Stopping the drug

  • Controlling the fever

  • Providing intensive supportive care

People with neuroleptic malignant syndrome are usually treated in an intensive care unit. The drug that caused neuroleptic malignant syndrome is stopped and fever is controlled, usually by wetting (misting) and blowing air over the skin or by using special cooling blankets. People who are very agitated are given sedatives by vein. Other treatments of possible but unproven benefit are often used because of the severity of this condition. These include dantrolene (a muscle relaxant, to reduce fever and muscle damage) and bromocriptine (to improve nerve function).

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