Serotonin Syndrome

Written by Mary Anne Dunkin
Medically Reviewed by Smitha Bhandari, MD on March 17, 2022

Serotonin syndrome is when your body has too much of a chemical called serotonin, usually because of a medication or combinations of medications.

Your body makes serotonin to help your brain cells and other nervous system cells communicate with each other. Researchers think a lack of serotonin in your brain may play a role in depression. But too much of it can lead to extreme nerve cell activity and dangerous symptoms.

Serotonin syndrome symptoms often begin hours after you take a new medication that affects your serotonin levels or after you raise your dose of a current drug. Symptoms may include:

In severe cases, serotonin syndrome can be life-threatening. Call 911 or go to the emergency room if you have any of these symptoms:

Medications usually cause serotonin syndrome, especially certain antidepressants. You might be at higher risk if you take two or more drugs and/or supplements that affect your serotonin levels.

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed class of antidepressants. They work by raising your serotonin levels. These drugs include:

Other prescription and over-the-counter drugs that can raise serotonin levels, either alone or when you take them together, include:

Some recreational drugs, such as LSD and cocaine, and dietary supplements, including St. John's wort and ginseng, can also cause serotonin syndrome when you take them with these antidepressants.

The FDA has asked drugmakers to add warning labels about the risk of serotonin syndrome. If you have questions about a medication, check the label or ask your doctor. Don't stop taking any medication before talking to your doctor.

Without treatment, serotonin syndrome can cause seizures, kidney failure, trouble breathing, coma, and death.

No single test can tell your doctor that you have serotonin syndrome. Instead, they’ll ask about your medical history -- including your use of medications, supplements, and recreational drugs -- and do a physical exam. They may order lab tests to rule out other health conditions that can look like serotonin syndrome, such as tetanus, sepsis, encephalitis, or heatstroke.

You’ll probably need to stay in the hospital so your doctor can treat your symptoms and monitor your recovery.

Removing the drug that caused your serotonin syndrome is crucial. You’ll probably feel better within a day of stopping the medication, although some drugs can take longer to leave your system. You might also need to get fluids through a vein (intravenous, or IV).

In severe cases, you might take a medication called cyproheptadine (Periactin) to keep your body from making serotonin.

Be sure your doctor knows about all the medications and supplements you take and any reactions you have, especially if you get prescriptions from more than one place.

If you use more than one drug that affects your serotonin levels, know the symptoms of serotonin syndrome so you can watch for them.

Show Sources

SOURCES: 

American Headache Society: "What is Serotonin Syndrome and What Should You Know About It?"

National Cancer Institute: "Serotonin."

OhioHealthOnline: "Serotonin Syndrome."

MedlinePlus: "Serotonin Syndrome."

Agency for Healthcare Research and Quality: "New report finds little evidence to determine the usefulness of genetic tests in the treatment of depression."

The NewEngland Journal of Medicine: "The Serotonin syndrome."

Merck Manual Consumer Version: “Serotonin Syndrome.”

The Ochsner Journal: “Serotonin Syndrome.”

American Family Physician: “Prevention, Diagnosis, and Management of Serotonin Syndrome.”

UpToDate: “Serotonin syndrome (serotonin toxicity).”

Cleveland Clinic: “Serotonin Syndrome.”

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