What are the symptoms of serotonin syndrome (SSRI) withdrawal?

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Last updated: March 2, 2025 • View editorial policy

From the Guidelines

Serotonin syndrome withdrawal, also known as discontinuation syndrome, is characterized by symptoms such as dizziness, fatigue, lethargy, general malaise, myalgias, chills, headaches, nausea, vomiting, diarrhea, insomnia, imbalance, vertigo, sensory disturbances, paresthesias, anxiety, irritability, and agitation, which can occur after missed doses or acute discontinuation of shorter-acting SSRIs, notably paroxetine, fluvoxamine, and sertraline 1. When considering the symptoms of serotonin syndrome withdrawal, it is essential to note that the severity and presentation can vary based on the specific medication, dosage, duration of treatment, and individual factors. Some key points to consider include:

  • The symptoms typically begin within days of reducing or stopping the medication and can last for weeks 1.
  • A discontinuation syndrome has been reported following missed doses or acute discontinuation of shorter-acting SSRIs, notably paroxetine, but also (to a lesser extent) fluvoxamine and sertraline 1.
  • To minimize these effects, medications should be tapered gradually under medical supervision rather than stopped suddenly.
  • The withdrawal occurs because the brain has adapted to the medication's effects on serotonin levels, and needs time to readjust when the medication is removed.
  • Anyone experiencing these symptoms should consult their healthcare provider, who may recommend slowing the tapering schedule or providing supportive treatments to manage symptoms during the discontinuation process. It is crucial to prioritize a gradual tapering schedule under medical supervision to minimize the risk of discontinuation syndrome and ensure a safe and effective treatment plan 1.

From the FDA Drug Label

Serotonin Syndrome — The development of a potentially life–threatening serotonin syndrome may occur with SNRIs and SSRIs, including Prozac treatment, particularly with concomitant use of serotonergic drugs (including triptans) and with drugs which impair metabolism of serotonin (including MAOIs). Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

The symptoms of serotonin syndrome associated with SSRI withdrawal are not directly addressed in the provided drug label. However, the label does describe the symptoms of serotonin syndrome, which may include:

  • Mental status changes: agitation, hallucinations, coma
  • Autonomic instability: tachycardia, labile blood pressure, hyperthermia
  • Neuromuscular aberrations: hyperreflexia, incoordination
  • Gastrointestinal symptoms: nausea, vomiting, diarrhea It is essential to note that these symptoms are associated with serotonin syndrome in general, not specifically with SSRI withdrawal 2.

From the Research

Symptoms of Serotonin Syndrome (SSRI) Withdrawal

  • The symptoms of serotonin syndrome are characterized by mental status changes, autonomic instability, and neuromuscular hyperactivity 3
  • These symptoms can include spontaneous clonus, inducible clonus with agitation or diaphoresis, ocular clonus with agitation or diaphoresis, tremor and hyperreflexia, or hypertonia, temperature above 100.4 degrees F (38 degrees C), and ocular or inducible clonus 3
  • Withdrawal symptoms from antidepressant drugs, particularly selective serotonin reuptake inhibitors, can occur during tapering and/or after discontinuation, and may include loss of treatment efficacy, refractoriness, switch into mania/hypomania, or paradoxical reactions 4
  • The oppositional model of tolerance provides a pathophysiologic basis for understanding and managing withdrawal syndromes, but alternative strategies that do not encompass continuation of antidepressant treatment are required 4
  • Serotonin syndrome can range in severity from mild to life-threatening, and clinical manifestations are diverse and nonspecific, which may lead to misdiagnosis 5
  • Symptoms of serotonin syndrome can include alteration of mental status, abnormalities of neuromuscular tone, and autonomic hyperactivity, but all three may not occur simultaneously 5

Management of Serotonin Syndrome

  • Management of serotonin syndrome involves withdrawal of the offending agent(s), aggressive supportive care to treat hyperthermia and autonomic dysfunction, and occasionally the administration of serotonin antagonists--cyproheptadine or chlorpromazine 3, 5
  • Patients with moderate and severe cases of serotonin syndrome require inpatient hospitalization 3, 5
  • Most cases of serotonin syndrome are mild and resolve with prompt recognition and supportive care, and with prompt recognition and supportive care, more severe cases have a favorable prognosis 3, 5

References

Guideline

clinical practice guideline for the assessment and treatment of children and adolescents with anxiety disorders.

Journal of the American Academy of Child and Adolescent Psychiatry, 2020

Research

Overview of serotonin syndrome.

Annals of clinical psychiatry : official journal of the American Academy of Clinical Psychiatrists, 2012

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.