Serotonin Syndrome: Causes, Signs, and Drugs That Trigger It

When your body gets too much serotonin, a chemical your brain and nerves use to 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 about feeling a little extra happy. It’s about your nervous system going into overdrive because too many drugs are pushing serotonin levels past safe limits.

You don’t need to take five different pills to trigger this. Sometimes, just adding a common SSRI, a type of antidepressant like sertraline or fluoxetine to your existing meds can do it. People on SSRIs for depression often add pain meds like tramadol or migraine drugs like triptans, not realizing they’re stacking serotonin boosters. Even some herbal supplements like St. John’s wort or certain cough syrups with dextromethorphan can push you over the edge. And it’s not just SSRIs—MAOIs, certain opioids, and even some antibiotics like linezolid can play a part. The real danger? Many doctors don’t test for it, and patients don’t connect the dots between new symptoms and new meds.

The signs are hard to miss if you know what to look for. Think muscle rigidity, shaking, high fever, fast heart rate, confusion, or sudden changes in blood pressure. If you’re on antidepressants and suddenly feel like you’re melting down from the inside, don’t wait. This isn’t anxiety. It’s your body screaming for help. The good news? If caught early, it’s treatable. Stop the offending drugs, get fluids, and get monitoring. But if you ignore it, it can lead to seizures, kidney failure, or worse.

The posts below cover real cases and common traps. You’ll find how serotonin syndrome shows up in older adults on SSRIs, what drugs to avoid with common pain relievers, and how to spot the warning signs before it’s too late. No fluff. Just what you need to protect yourself or someone you care about.

17 Nov 2025
by Michael Brown
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St. John’s Wort and SSRIs: The Hidden Danger of Serotonin Syndrome

Mixing St. John’s Wort with SSRIs can cause serotonin syndrome-a dangerous, sometimes fatal condition. Learn why this herbal supplement isn't safe with antidepressants and what to do instead.