What is serotonin syndrome?
Last updated September 3, 2026.
Too much serotonin activity, usually from combining drugs that each raise it - an SSRI plus a triptan, tramadol, St John's Wort, dextromethorphan, or MAOIs - or from a dose jump. The NHS symptom list: fast heartbeat, sweating, shaking, twitching muscles, confusion or agitation - plus high temperature and diarrhea in the classic picture. It starts within hours of the trigger. Mild cases settle when the drug is stopped; severe cases (very high temperature, rigid muscles, seizures) are emergencies. Prevention is one habit: every prescriber and pharmacist knows your full list before adding migraine, pain, cough, or herbal products. Agitation plus sweating plus twitching within hours of a new combination is a same-day call. Pymander is a free AI doctor, 24/7 by text, and can check a combination first.
What to do
- Declare the antidepressant everywhere: migraine and cough meds included.
- Skip St John's Wort on SSRIs: the herbal trap.
- Hours after a new combo? Watch for the cluster: fast heart, sweat, twitch, confusion.
- Severe signs = emergency care: high temperature, rigidity, seizures.
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