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Serotonin Syndrome Signs: What to Watch For and When to Call
Serotonin syndrome signs include agitation, diarrhea, a fast heartbeat, hallucinations and a higher body temperature. They can start within minutes to hours after two serotonin-affecting medicines are combined, or after a dose increase. Untreated, it can be deadly, so call your provider right away.
By the MemoPryl label deskUpdated · 4 min read
What are the signs of serotonin syndrome?
The main signs are agitation, diarrhea, a fast heartbeat, hallucinations and a rise in body temperature. They can appear within minutes to hours (MedlinePlus, Serotonin syndrome).
MedlinePlus explains that the problem usually happens when two or more medicines that affect serotonin are taken together. Its example is a triptan combined with an SSRI or SSNRI. The risk is higher when you first start a medicine or raise the dose (MedlinePlus, Serotonin syndrome).
Left untreated, serotonin syndrome can be deadly. That is why speed matters more than certainty. You do not need to be sure before you call.
| Sign | What it can look like |
|---|---|
| Agitation | Restless, on edge, cannot settle |
| Diarrhea | Sudden, new, more than usual |
| Fast heartbeat | Racing or pounding at rest |
| Hallucinations | Seeing or hearing things that are not there |
| Higher body temperature | Feeling hot, sweating, fever |
Can a supplement like St. John's wort cause it?
St. John's wort can contribute to it. NCCIH says combining the herb with certain antidepressants or other serotonin-affecting drugs may lead to serious serotonin-related side effects (NCCIH, St. John's Wort safety).
MSK also reports serotonin syndrome, especially when St. John's wort is combined with prescription antidepressants (MSK, St. John's Wort). Note that the MedlinePlus page itself does not speak to supplements, so the supplement link comes from NCCIH and MSK.
St. John's wort is one of six ingredient names tied to MemoPryl on a sibling pack. That list is unconfirmed for the bottle you receive, and no amounts are printed on any image we have. If your bottle lists it, ask first.
Thinking about MemoPryl?Check your medicines with a pharmacist first. The checkout confirms prices and the 60-day window.
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Who should be most careful?
Anyone who takes an antidepressant, a migraine medicine such as a triptan, or any other medicine that acts on serotonin should ask before adding a supplement.
- You take a prescription antidepressant.
- You are about to start a new medicine or raise a dose.
- You take a migraine medicine and a supplement together.
- You are not sure what is in your bottle.
Show your pharmacist the bottle, or a photo of the label. When the panel is missing, say so. A pharmacist cannot check what is not printed. The MemoPryl medicine guide lists the full set of cautions.
MemoPryl: capsules in 2, 3 or 6 bottlesRead the bottle · check medicines first · 60-day window (confirm)
See packsWhat should I do if I think it is happening?
Contact your provider right away if you have symptoms, and call emergency services if they are severe (MedlinePlus, Serotonin syndrome).
Do not stop your prescribed medicine on your own. MedlinePlus says to call your provider first (MedlinePlus, Serotonin syndrome). Bring the supplement bottle with you.
Keep taking prescribed medicine as directed, and ask your doctor or pharmacist before you start any supplement. This post is general information, not medical advice.
How can I lower the chance of a bad mix?
Ask before you start, change one thing at a time, and keep one written list of everything you take.
New products and new doses are when the risk is higher (MedlinePlus, Serotonin syndrome). Add one item, tell your pharmacist, and wait for their answer before adding another. See also the side effects page.
FAQ01
Questions people ask about MemoPryl
How fast can serotonin syndrome start?
It can start within minutes to hours after you combine two serotonin-affecting medicines or raise a dose. Do not wait for it to pass. Call your provider right away if you notice the signs.
Does St. John's wort interact with antidepressants?
Yes. NCCIH says combining St. John's wort with certain antidepressants may cause a serious rise in serotonin. Ask your doctor or pharmacist before you use it, and keep taking your prescription as directed.
Should I stop my antidepressant if I feel strange after a supplement?
No, not on your own. Call your provider right away, describe the symptoms and the supplement, and bring the bottle. They will tell you what to change, if anything.
Who wrote this02
Written and reviewed by
Each page draws on the bottle images, the seller's product notes and linked NIH, FDA, FTC and peer-reviewed sources.
Last updated . See our editorial standards and how we check reviews. This website is run by MemoPryl USA retail, not by the manufacturer or the distributor of the bottle. We are paid a commission when you buy through our order links.
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