Serotonin Syndrome Symptoms and Treatment

Know What to Look For

Multiple drug bottles, some tipped over, and different kinds of drugs spilled.
Combining certain drugs can lead to serotonin syndrome. Comstock/Getty Images

When you have fibromyalgia, chronic fatigue syndrome, major depression, or another condition treated with drugs that boost serotonin levels or activity, you may be at risk for serotonin syndrome. It's a dangerous and potentially life-threatening condition, so you want to make sure you know how to spot it.

You're most at risk when you start a new drug, increase your dosage, or add a second serotonin-affecting drug to your regimen.

Some supplements may also contribute to serotonin syndrome.

What is Serotonin?

Serotonin plays major roles in several of your body's systems. In the brain, it's a neurotransmitter, carrying messages from one neuron to the next. It's thought to be involved in pain regulation, sleep, alertness, memory, mood, social function, and sexual desire. You can probably see now why it's involved in these conditions.

In the rest of your body, it's a hormone, with almost all of it concentrated in digestive system. There's it's believed to be involved in digestion and appetite. Serotonin is implicated in irritable bowel syndrome, which is a close relative of fibromyalgia and chronic fatigue syndrome.

For your body to function properly, serotonin activity needs to stay within certain parameters. If you have one of these conditions, you're likely familiar with symptoms of low or sluggish serotonin. However, in this case, you can have too much of a good thing—so much, in fact, that it can threaten your life.

Serotonin Syndrome Symptoms

Serotonin syndrome typically comes on within just one day of changing a drug or starting a new one. A similar condition called neuroleptic malignant syndrome usually develops more slowly and may strike weeks after you change medications.

To help your doctor distinguish between these two conditions, make sure to provide a complete medical history and list of medications that includes starting dates.

The most common symptoms of serotonin syndrome include:

  • sudden jerky or shock-like movements
  • flushed or pale complexion
  • slow, fast or irregular heart beat
  • fever
  • headache
  • anxiety
  • rigid muscles
  • confusion (different from "brain fog" or "fibro fog")
  • restlessness
  • profuse sweating
  • tremor
  • poor coordination (over-responsive reflexes, difficulty controlling movements)
  • rapid breathing
  • high blood pressure
  • shivering

You might also feel sick if you stop taking an SSRI antidepressant abruptly or too quickly, but discontinuation symptoms are different from those of serotonin syndrome. See SSRI Discontinuation Syndrome for more information.

If you're switching from one serotonin-affecting drug to another, be sure to follow your doctor's instructions. Some of these drugs take a couple of weeks to be completely out of your system, so starting a new one too soon can be dangerous.

Some symptoms of serotonin syndrome are also common in fibromyalgia or chronic fatigue syndrome, such as headache and anxiety. If you have a sudden increase in the severity of these symptoms, it's important to consider serotonin syndrome rather than to assume they're due to your condition.

Treating Serotonin Syndrome

If your doctor diagnoses serotonin syndrome, the first line of treatment is to get you off of all drugs that raise available amounts of serotonin. Again, don't discontinue these kinds of drugs on your own—be sure you talk to your doctor about getting off of them safely.

In some cases, doctors will administer drugs that help lower serotonin levels. For muscle symptoms, a type of drug called benzodiazepines may help. Some people also need treatment for respiratory distress.

Typically, symptoms fade quickly after treatment begins, and most people make a full recovery. If the condition is missed, however, serotonin syndrome can be fatal, so it's important to get medical help immediately if you develop symptoms shortly after starting something new that alters serotonin function.

Antidepressants & Serotonin Syndrome

Several classes of antidepressants have been implicated in cases of serotonin syndrome, and those classes include some of the most frequently prescribed drugs for fibromyalgia and chronic fatigue syndrome. They're detailed below, along with some of the popular drugs from those classes. This is not a comprehensive list, so if you're taking something not listed, ask your doctor or pharmacist what class it's in.

SSRI/SNRI Antidepressants:

SSRIs (selective serotonin reuptake inhibitors) and SNRIs (serotonin norepinephrine reuptake inhibitors) both make more serotonin available to your brain by slowing down a process called reuptake.

Drugs in this class include:

Learn more: SSRIs/SNRIs for Fibromyalgia & Chronic Fatigue Syndrome

Tricyclic Antidepressants

Tricyclics are an older type of antidepressant that blocks the breakdown of serotonin and/or norepinephrine in your brain, keeping more of it available.

Drugs in this class include:

Learn more: Tricyclic Antidepressants

MAOI Inhibitors

Monoamine oxidase inhibitors (MAOIs) are prescribed less often than some antidepressants because you have to make dietary changes to take them safely. They also interact negatively with certain drugs. MAO is an enzyme that breaks down serotonin and some other neurotransmitters, and these drugs block it.

  • Emsam (selegiline)
  • Marplan (isocarboxazid)
  • Nardil (phenelzine)
  • Parnate (tranylcypromine)

Learn more: MAOI Inhibitors

Other Antidepressants

At least two antidepressants from outside the classes above have been linked to cases of serotonin syndrome. They are:

  • bupropion
  • trazodone

Other Prescription Drugs & Serotonin Syndrome

Several other types of medications are linked to serotonin syndrome as well. You may be prescribed one or more of these to help control symptoms of fibromyalgia or chronic fatigue syndrome, or for a separate condition.

Certain pain killers:

Dopamine agonists:

  • amantadine
  • bromocriptine
  • levodopa

Triptans, which are used to treat migraine and cluster headaches.

Other drugs:

  • linezolid
  • dextromethorphan
  • lithium

Non-Prescription Substances & Serotonin Syndrome

A few herbal and nutritional supplements are believed to increase your risk of developing serotonin syndrome. They include:

Make sure your doctor knows about all of the supplements you're taking. It's also a good idea to run them by your pharmacist.

Some recreational drugs can increase serotonin activity to a dangerous degree, as well. They are:

  • amphetamines
  • cocaine
  • ecstacy
  • LSD

While it may be uncomfortable, you need to be honest with your doctor about any recreational drug use. Your doctor's job is to keep you as safe and healthy as possible, and this is part of that. If you believe you have a drug addiction, here are some resources that can help:

Sources:

Gomersall, C. Serotonin Syndrome.

Zagaria, M. Serotonin Syndrome: Identification, Resolution, and Prevention.

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