Serotonin Syndrome – Symptoms and Causes
What is Serotonin Syndrome
Serotonin syndrome occurs when the body has too much serotonin, a natural chemical needed for nerve and brain function. This serious reaction happens when certain drugs cause serotonin levels to become too high in the body.
The condition can range from mild symptoms like shivering and diarrhea to severe effects including muscle stiffness, high fever, and seizures. Without proper treatment, severe cases can be fatal.
This condition typically develops when someone:
- Increases their dose of a serotonin-affecting medication
- Starts taking a new drug that affects serotonin
- Combines two or more medications that contain serotonin (like taking both a migraine medication and an antidepressant)
Some recreational drugs and dietary supplements can also trigger serotonin syndrome.
Mild cases may improve within 1โ2 days after:
- Stopping the medications causing symptoms
- Taking medications that block serotonin effects
If you experience symptoms after starting a new medication, seek medical help immediately.
Symptoms
Serotonin syndrome signs often appear within hours after starting a new medication or increasing a current dosage.
Common symptoms include:
- Feeling restless or agitated
- Trouble sleeping
- Mental confusion
- Fast heartbeat
- Widened pupils
- Muscle twitching or coordination problems
- High blood pressure
- Stiff muscles
- Excessive sweating
- Loose stools
- Headaches
- Shivering
- Goose bumps
Life-threatening symptoms can develop in severe cases:
- Dangerously high fever
- Strong tremors
- Seizure activity
- Abnormal heart rhythm
- Loss of consciousness
Seek medical help immediately if you notice these symptoms, especially after changing medications that affect serotonin levels.
When to Get Medical Help
If you think you might have serotonin syndrome after starting a new medication or increasing your dosage, contact your healthcare provider immediately or go to the emergency room. Don’t wait to see if symptoms improve on their own.
Causes
Serotonin syndrome happens when too much serotonin builds up in your body. Serotonin is an important chemical that helps control many body functions.
Your brain and spinal cord make serotonin to help manage attention, behavior, and body temperature. It’s also made in your intestines to help with digestion, blood flow, and breathing.
Most cases of serotonin syndrome occur when people take two or more medications that increase serotonin levels. For instance, combining an antidepressant with a migraine drug or an opioid pain medication can trigger this condition.
Some people may develop symptoms from just one serotonin-boosting medication. Deliberate overdoses of antidepressants can also cause serotonin syndrome.
Many medications can lead to serotonin syndrome, including:
Antidepressants:
- SSRIs (like Prozac, Zoloft, Lexapro)
- SNRIs (such as Cymbalta, Effexor XR)
- Bupropion
- Tricyclic antidepressants
- MAOIs
Other Prescription Medications:
- Migraine treatments (including triptans)
- Opioid pain relievers (codeine, tramadol, fentanyl)
- Lithium (mood stabilizer)
- Anti-nausea drugs
- Certain antibiotics
- Some HIV medications
Non-Prescription Sources:
- Illicit drugs (ecstasy, LSD, cocaine)
- Herbal supplements (St. John’s wort, ginseng)
- Over-the-counter cold medicines with dextromethorphan
The risk increases significantly when these substances are combined. For example, taking an SSRI antidepressant with a triptan migraine medication can be dangerous. Similarly, using St. John’s wort (which naturally increases serotonin) while on a prescribed antidepressant raises the risk.
Risk Factors
Some people face higher chances of developing serotonin syndrome than others, though it can affect anyone. Risk factors include:
- Starting a new medication that increases serotonin or raising your current dose
- Taking multiple medications that boost serotonin levels at the same time
- Using herbal supplements known to raise serotonin levels in the body
- Using illegal drugs that increase serotonin levels
Combining these factors can significantly raise your risk. Mixing different antidepressants or prescription medications with certain herbal products can dangerously increase serotonin levels in the body.
Complications
Serotonin syndrome usually resolves without lasting problems when serotonin levels return to normal. However, severe cases can become dangerous if not treated quickly.
Without proper medical care, a person with serious serotonin syndrome may become unconscious or, in the worst situations, die.
Prevention
Reducing your risk of serotonin syndrome requires careful medication management. Taking multiple serotonin-affecting drugs or increasing your dosage can raise your chances of developing this condition.
Always maintain a complete list of your medications. Share this list with healthcare providers and pharmacists at every visit. This helps them identify potential drug interactions that could lead to serotonin syndrome.
Important safety steps:
- Discuss any previous medication reactions with your doctor
- Ask about potential risks before starting new treatments
- Never stop medications without medical guidance
- Ensure all your doctors know about prescriptions from other providers
If you need to combine serotonin-affecting medications, be vigilant about possible symptoms. Your doctor can help determine if the benefits of specific drug combinations outweigh the risks in your situation.
When seeing multiple healthcare providers, always keep each one informed about changes to your medication regimen to prevent dangerous interactions.
