Serotonin Syndrome: Signs, Causes, and What to Do If You Suspect It

When your body gets too much serotonin, a natural chemical that helps regulate mood, sleep, and digestion. Also known as serotonin toxicity, it’s not just a side effect—it’s a medical emergency that can turn deadly in hours. This isn’t rare. It happens when you mix medications that boost serotonin, like antidepressants, painkillers, or even some herbal supplements. The body doesn’t know how to handle the flood, and your nervous system starts overloading.

You might not realize it at first. Early signs look like anxiety, restlessness, or a slight fever. But then things move fast: muscle twitching, rigid muscles, heavy sweating, confusion, or a racing heart. In severe cases, your body temperature can spike above 104°F, your blood pressure goes wild, and you could slip into seizures or lose consciousness. SSRIs, a common class of antidepressants including fluoxetine and sertraline are often involved, but so are triptans, medications used for migraines, certain pain meds like tramadol, and even St. John’s wort. The danger isn’t just one drug—it’s the combo. That’s why drug interactions, when two or more medicines react unpredictably are the biggest red flag.

It’s not about taking too much of one pill. Sometimes it’s just adding a new medicine without telling your doctor. Or switching from one antidepressant to another too quickly. Or grabbing an over-the-counter cough syrup that contains dextromethorphan while already on an SSRI. These aren’t edge cases—they’re everyday mistakes. And they happen because most people don’t know serotonin syndrome exists until it’s too late.

If you’re on any antidepressant, migraine treatment, or chronic pain medication, you need to know the signs. Don’t wait for a doctor to tell you. If you feel off after starting or changing a drug—especially if you’re dizzy, shaky, or unusually hot—trust your gut. Call your doctor or go to the ER. Waiting even an hour can make a difference between recovery and disaster.

Below, you’ll find real stories and facts from people who’ve been there. We cover what triggers it, which drugs are most likely to cause it, how to spot it early, and what to do if you think you’re in danger. No fluff. No jargon. Just what you need to stay safe.