Neuroleptic Malignant Syndrome: Prevention, Causes, and Treatment
Key takeaways:
Neuroleptic malignant syndrome (NMS) is a rare condition that can happen when someone takes antipsychotic or antidepressant medications.
People taking antipsychotic medications at high doses are more likely to develop NMS.
NMS is life-threatening, and its treatment requires hospitalization.
Neuroleptic malignant syndrome (NMS) is a condition that develops when medications block dopamine, a chemical in the brain. NMS is a rare but serious condition that can be fatal if it isn’t treated quickly. Several types of medications can cause NMS, but antipsychotics are the most common instigators.
If you or someone you love is taking medications that can lower dopamine levels, here’s everything you need to know about NMS.
What causes neuroleptic malignant syndrome?
NMS happens when dopamine levels in the brain drop quickly. Dopamine plays an important role in controlling:
Heart rate
Blood pressure
Breathing rates
Body temperature
When dopamine levels are too low, the body has trouble with these important functions. This can lead to serious illness and even death.
What medications are associated with neuroleptic malignant syndrome?
Several medications can lead to NMS, including certain antipsychotic and antidepressant medications. It’s important to remember that NMS is rare. It’s good to be aware of NMS, but don’t stop your medication without talking to your healthcare provider. It’s very likely that your medication’s benefits far outweigh your risk of developing NMS.
Antipsychotic medications
Antipsychotics can treat schizophrenia, bipolar disorder, and depression. Higher-potency (strength) antipsychotics are more likely to cause NMS than lower-potency antipsychotics.
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Commonly prescribed higher-potency antipsychotics include:
Haloperidol
Fluphenazine
Chlorpromazine
Trifluoperazine
Prochlorperazine
Antidepressant medications
Certain antidepressants used to treat depression and anxiety can cause NMS. These medications include:
Phenelzine
Amoxapine
Dosulepin
Desipramine
Huntington’s disease medications
Tetrabenazine is a drug used to treat Huntington's disease. Tetraneanzine reduces involuntary movements by decreasing dopamine. Although rare, it can cause NMS.
Anti-nausea medications
While rare, certain medications used to treat nausea and vomiting can also cause NMS. These medications include:
Parkinson’s disease medications
Medications used to treat Parkinson’s disease improve symptoms by increasing dopamine levels. In this case, people develop NMS when these medications are stopped. These medications include:
Carbidopa/levodopa (Sinemet)
If you have Parkinson’s disease and take these medications, never stop taking them without talking to your healthcare provider. You may need to slowly lower your dose over time to prevent side effects, including NMS.
What is the ‘tetrad of symptoms’?
The “tetrad of symptoms” refers to the four most common symptoms of NMS, which are:
1) Fever
2) Rigid muscles
3) Confusion
4) Uncontrollable changes in heart rate, blood pressure, and breathing
These symptoms are severe and can be life-threatening. If your loved one is taking medication that can cause NMS and they suddenly develop fever, confusion, and they aren’t looking well, seek medical care right away. Your loved one may not be able to call for help themselves,
What’s the treatment for neuroleptic malignant syndrome? Is there a cure?
People with NMS need to be treated in a hospital. The first step is to stop all medications that decrease dopamine. People will also commonly receive treatment like:
Intravenous (IV) fluids
Oxygen therapy
Medications like lorazepam, dantrolene, and bromocriptine
Most episodes of NMS improve with treatment. Without treatment, mortality may be as high as 20%. So it’s important to get care right away.
What can you do to lower your risk?
It’s unclear why some people get NMS and others don’t — even if they use the same medication.
But there are some things you can do to lower your risk of developing NMS. If possible:
Use an antipsychotic that has less effect on your dopamine levels — like quetiapine, clozapine, or chlorpromazine.
Use the lowest dose of medications that decrease dopamine.
Avoid taking lithium if you are already taking an antipsychotic or antidepressant that lowers dopamine levels.
Try not to take more than one medication that decreases dopamine levels.
Drink enough fluids every day so your body can process your medication.
The bottom line
Neuroleptic malignant syndrome is a rare but serious condition that can cause damage to the heart, brain, and lungs. NMS develops in some people who take medications that lower the amount of dopamine in the brain. Certain types of antipsychotics and antidepressants are more likely to cause NMS than others. To decrease your risk of developing NMS, try not to take more than one medication that decreases dopamine levels.
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References
Lev, R., et al. (1994). Neuroleptic malignant syndrome presenting without fever: Case report and review of the literature. Journal of Emergency Medicine.
Patel, K., et al. (2018). A case of neuroleptic malignant syndrome in a profoundly intellectually disabled patient with successful reintroduction of antipsychotic therapy with quetiapine. Case Reports in Psychiatry.
Shiloh, R., et al. (2003). Precautionary measures reduce risk of definite neuroleptic malignant syndrome in newly typical neuroleptic-treated schizophrenia inpatients. International Clinical Psychopharmacology.
Strawn, J., et al. (2007). Neuroleptic malignant syndrome. American Journal of Psychiatry.
