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Topic: Neuroleptic malignant syndrome
Word Count – 500W


Neuroleptic Malignant Syndrome – Causes, Symptoms, and Treatments

Neuroleptic malignant syndrome (NMS) can be considered as a rare but life-threatening reaction to all antipsychotic drugs which treat bipolar disorder, schizophrenia, and various mental health conditions. NMS tends to affect our nervous system and is known to cause symptoms like muscle stiffness and high fever. But although life-threatening, thankfully, this syndrome is treatable, and if found early on, chances of full recovery are extremely high. In this article, we are going to talk about the causes, symptoms, and treatment of the neuroleptic malignant syndrome.


NMS is a rare condition, and only 1 to 2 people in every ten thousand who have consumed antipsychotic drugs end up with NMS. Both older and newer antipsychotic drugs like Chlorpromazine (Thorazine), Haloperidol (Haldol) to Clozapine (Clozaril), to Olanzapine (Zyprexa) can cause NMS. These drugs tend to block the brain chemical named dopamine, and what this does is make the muscle stiff while also causing rigid movements in individuals suffering from Parkinson’s disease.

All antipsychotic drugs are capable of causing NMS. But some stronger drugs like haloperidol and fluphenazine are much more likely to trigger NMS.

NMS is much more likely in men than women. And chances of ending up with NMS is higher if you

  • Have consumed a high dose of an antipsychotic drug
  • Switched from one drug to a new one
  • Quickly increased the dose of the drug
  • Got the medicine in the form of a shot

Now there are some drugs like Droperidol (Inapsine), Promethazine (Phenergan) that are used for treating vomiting and nausea and can block dopamine production, thereby causing NMS.


Symptoms usually start showing within a couple of weeks of starting the medicine or changing the dosage. But there are cases when symptoms might start showing just after few days or even months. These symptoms last for around ten days and can include:

  • Stiffness of the muscles
  • Sweating profusely
  • High fever
  • Changes in the mental state and being anxious
  • Abnormally fast heartbeat
  • Salivating more than usual
  • Heavy breathing

NMS is capable of damaging muscles and also can cause low or high blood pressure. If not treated properly and quickly, the following problems can happen:

  • Lung, heart, kidney failure
  • Lacking oxygen in the body
  • More acid production in the body
  • Lung infection is caused by breathing in the fluid


As the first step, doctors usually take the patient off the antipsychotic drugs causing NMS. In most cases, patients get their treatment in the intensive care unit of the hospital. The goal at this point remains of bringing down the fever and giving nutrition and fluids.

Medicines that help with NMS are Dantrolene (Dantrium) which helps to relax tight muscles, and Bromocriptine (Parlodel) which makes the body produce more dopamine. In case these medicines fail to help doctors go for electroconvulsive therapy, which is pain-free.

It usually takes 2 weeks for NMS to get better, and once you have recovered, you can go back to taking your antipsychotic drug again. There are always chances of NMS coming back; this is why you need to be under the constant supervision of the doctor. Keep in mind the longer you wait to go back on your medications lesser the chances of getting NMS again are there.