Conditions and symptoms
What Is Serotonin Syndrome? Signs and Why Labels Warn
Serotonin syndrome · say it: seh-ruh-TOE-nin SIN-dromeAlso written: serotonin toxicity, serotonergic syndrome
Short answer
Serotonin syndrome is a potentially serious reaction caused by too much serotonin activity, often from combining certain medicines. It needs urgent care.
What it means
Serotonin syndrome happens when there is too much serotonin activity in the nervous system. It can cause agitation or confusion, a fast heartbeat, sweating, shivering, muscle twitching or stiffness, diarrhoea and a high temperature. It can be serious, so anyone with these signs after starting or combining medicines needs urgent medical help.
Labels for antidepressants (such as SSRIs, SNRIs and MAOIs), some pain medicines, triptans and some other medicines warn about it because the risk rises mainly when two or more medicines that raise serotonin are taken together, or when a dose changes. The warning is telling you to make sure every prescriber and your pharmacist knows everything you take, including herbal products.
It is different from the mild, short-lived side effects many people notice when starting an antidepressant, such as an upset stomach. It is also different from neuroleptic malignant syndrome, a separate rare reaction linked to antipsychotic medicines.
Where you may see it
- The 'Warnings and precautions' section of antidepressant labels
- Drug interaction warnings in pharmacy leaflets
- Labels for triptans and some opioid pain medicines
📄 How it looks on a report
Serotonin syndrome has been reported with SSRIs, particularly with concomitant use of other serotonergic drugs.
🙅 What it does not mean
- It does not mean you should stop your medicine on your own. Stopping some medicines suddenly can cause other problems, so talk to your prescriber.
- It does not mean you cannot ever take two of these medicines together. Doctors sometimes combine them with care.
- Being listed on a label does not mean it is likely to happen to you.
🎯 Check yourself
Which of these is the right meaning of “Serotonin syndrome”?
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Serotonin syndrome”
Plain-English explanations of each medicine, from its official FDA label.
- Amitriptyline
An antidepressant of the tricyclic type
- Citalopram
a selective serotonin reuptake inhibitor (SSRI), a type of antidepressant medicine
- Duloxetine
A serotonin and norepinephrine reuptake inhibitor (SNRI) type of antidepressant medicine
- Escitalopram
a selective serotonin reuptake inhibitor (SSRI), a type of antidepressant
- Fluoxetine
a selective serotonin reuptake inhibitor (SSRI), a type of antidepressant medicine
- Lithium Carbonate
A mood-stabilizing agent, which the label describes as a medicine used to treat bipolar I disorder
- Mirtazapine
An antidepressant medicine. The label describes it as having a tetracyclic chemical structure and belonging to the piperazino-azepine group of compounds.
- Morphine Sulfate
a strong prescription opioid pain medicine (the label describes it as an opioid agonist)
- Ondansetron
A serotonin-3 receptor antagonist, a medicine that blocks serotonin 5-HT3 receptors to help prevent nausea and vomiting
- Paroxetine
A selective serotonin reuptake inhibitor (SSRI), a type of antidepressant medicine
🔗 Read more from trusted sources
- “Serotonin syndrome” on MedlinePlus ↗
US National Library of Medicine
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