Serotonin Syndrome
A potentially serious condition caused by excess serotonin activity
Severe serotonin syndrome is a medical emergency. If you suspect severe symptoms, call 911 or go to the nearest emergency room immediately.
What Is Serotonin Syndrome?
Serotonin syndrome occurs when there's too much serotonin activity in the nervous system. It's typically caused by medications that increase serotonin levels, especially when combining multiple serotonergic drugs or taking high doses.
The condition can range from mild (often resolving on its own) to severe and life-threatening. Symptoms usually begin within hours of starting a new medication, increasing a dose, or combining medications.
Symptoms of Serotonin Syndrome
Mild Symptoms
• Nervousness or restlessness
• Insomnia
• Nausea or diarrhea
• Dilated pupils
• Rapid heartbeat
• Tremor
Moderate Symptoms
• High blood pressure
• Elevated body temperature
• Agitation
• Increased reflexes
• Muscle twitching
• Heavy sweating
Severe Symptoms (Emergency)
• High fever (over 104°F)
• Seizures
• Irregular heartbeat
• Unconsciousness
• Muscle rigidity
• Loss of muscle coordination
What Causes Serotonin Syndrome?
Serotonin syndrome most commonly occurs when:
Combining serotonergic medications
Taking two or more drugs that increase serotonin
Overdose of a serotonergic drug
Taking too much of a single medication
Starting a new medication
Or increasing the dose of a serotonergic drug
Medications That Can Cause Serotonin Syndrome
Antidepressants
SSRIs, SNRIs, MAOIs, Tricyclics
Migraine Medications
Triptans (sumatriptan, etc.)
Pain Medications
Tramadol, fentanyl, meperidine
Supplements
St. John's Wort, 5-HTP, tryptophan
Anti-Nausea
Ondansetron (Zofran), metoclopramide
Illicit Drugs
MDMA (ecstasy), LSD, cocaine
Prevention
Treatment
Treatment depends on severity:
Mild Cases
Stop the offending medication(s). Symptoms usually resolve within 24-72 hours.
Moderate Cases
May require hospitalization, IV fluids, and medications to control symptoms.
Severe Cases
Requires emergency care, muscle relaxants, cooling measures, and possibly sedation and ventilation.
When to Seek Medical Help
- • You recently started or increased a serotonergic medication AND have symptoms
- • Symptoms are worsening or not improving after stopping medication
- • You have a high fever, seizures, or irregular heartbeat
- • You're confused, unconscious, or have severe muscle rigidity
Call 911 for severe symptoms. Call your doctor or our office for mild symptoms.
Questions About Your Medications?
Our psychiatric team can help ensure your medications are safe.