Bipolar Disorder Treatment Medications What Is Serotonin Syndrome? By Marcia Purse Marcia Purse is a mental health writer and bipolar disorder advocate who brings strong research skills and personal experiences to her writing. Learn about our editorial process Marcia Purse Medically reviewed by Medically reviewed by Steven Gans, MD on January 11, 2020 Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital. Learn about our Review Board Steven Gans, MD Updated on June 01, 2020 Print GregorBister / Getty Images Table of Contents View All What Is Serotonin Syndrome? Symptoms Diagnosis Causes Risk Factors Treatment What Is Serotonin Syndrome? Serotonin syndrome is a potentially life-threatening condition that's caused by elevated serotonin concentrations in your body from certain medications. Serotonin is a type of chemical known as a neurotransmitter that communicates with nerve cells and has a wide variety of functions throughout your body, primarily in your central nervous system and intestines. In the right amounts, serotonin is necessary for important bodily functions, but when your body builds up too much and your levels get too high, symptoms can range from unpleasant to severe. If it's left untreated, serotonin syndrome can potentially lead to death. Symptoms Symptoms of serotonin syndrome can be mild to severe indicating anything from a slight serotonin excess to a life-threatening imbalance. The most common symptoms include: AnxietyConfusionDilated pupilsFeverFlushing or palenessHeadacheHigh blood pressureIrregular heartbeatMuscle rigidityPoor coordinationProfuse sweatingRapid breathingRestlessnessShiveringSlow or fast pulseSudden jerky or shock-like movementsTremor If your condition becomes severe, it can turn into a life-threatening situation and may include signs like: High feverLosing consciousnessSeizuresSudden swings in your blood pressure and/or pulse If you suspect you or a loved one is showing signs of serotonin syndrome, contact your doctor immediately. If your symptoms are getting worse or they're severe, head to the emergency room or call 911. Immediate treatment is important because you can become seriously ill and your condition can become fatal the longer you go untreated. SSRI Discontinuation Syndrome It should be noted that some of the same symptoms listed above may also occur when you abruptly stop taking an antidepressant or you taper it off too quickly, known as SSRI discontinuation syndrome. Agitation, headaches, shock-like sensations, poor coordination, chills, and impaired concentration are some of the characteristics common to both syndromes. Because of this risk, it's vital that you never stop taking your antidepressant abruptly without discussing it with your doctor. How to Taper Off Your Antidepressant Diagnosis Because the symptoms are similar to many other issues, you won't be diagnosed with serotonin syndrome until every other possible diagnosis has been ruled out. This is mainly because serotonin syndrome has to be diagnosed purely on your symptoms, history, and your physical and neurological exam. Other conditions that need to be ruled out include: Infections like meningitis and encephalitisIntoxicationNeuroleptic malignant syndrome (NMS), another drug-related disorder that has some of the same symptoms as serotonin syndrome but results from antipsychotics (The biggest difference is that serotonin syndrome generally comes on quickly after starting the trigger medication.)Overdose of a substance like cocaineReactions to other medicationsWithdrawal from alcohol or drugs The tests your doctor may order to rule these conditions out include: Blood tests such as a complete blood count (CBC), blood cultures to test for infection, and other blood tests that check your electrolytes, screen for drugs and alcohol, and check your kidney, thyroid, and liver functionUrine tests to screen for drugs and alcohol, as well as to look at your kidney functionComputed tomography (CT) scan of your brainElectrocardiogram (ECT) to check your heartLumbar puncture (spinal tap) to evaluate your spinal fluidChest X-ray Causes Serotonin syndrome, also known as serotonin toxicity, happens as the result of taking serotonergic drugs, which are medications that affect the level of serotonin in your body. It may be brought on by several different circumstances including: Taking one serotonergic medication: It's unlikely that using one serotonergic medication by itself will cause serotonin syndrome, but it can happen in certain people who are sensitive to serotonin, especially when the dose is increased.Overdosing: You can end up with serotonin syndrome if you ingest too much of your serotonergic medication(s), whether or not overdose is an accident or purposeful.Taking two serotonergic medications together: The majority of cases of serotonin syndrome involve a person taking two (or more) serotonergic drugs at the same time, often without realizing it. Medications Associated With Serotonin Syndrome The medications that are most often associated with serotonin syndrome are antidepressants such as: Selective serotonin reuptake inhibitors (SSRIs) like Paxil (paroxetine), Prozac (fluoxetine), and Celexa (citalopram)Serotonin and norepinephrine reuptake inhibitors (SNRIs) like Cymbalta (duloxetine), Pristiq (desvenlafaxine), and Effexor (venlafaxine)Tricyclic antidepressants such as amitriptyline, Pamelor (nortriptyline), and Surmontil (trimipramine)Monoamine oxidase inhibitors (MAOIs) like Nardil (phenelzine) and Parnate (tranylcypromine)Atypical antidepressants like Wellbutrin (bupropion), which is also used for smoking cessation under the brand name Zyban There are other medications that are also considered serotonergic drugs, though they may not be as well-known. Some examples of these include: Migraine medications called triptans such as Axert (almotriptan), Amerge (naratriptan), Imitrex (sumatriptan), and Maxalt (rizatriptan)Anticonvulsants like Tegretol (carbamazepine) and Depakene (valproic acid), which are used for migraines, epilepsy, and bipolar disorderOpioid pain medications such as codeine, Ultram (tramadol), Demerol (meperidine), Talwin (pentazocine), and Oxycontin (oxycodone)5-HT3 receptor antagonists, which treat nausea, like Anzemet (dolasetron), granisetron, Zofran (ondansetron), and Aloxi (palonosetron)Reglan (metoclopramide), a prokinetic medication that's used to treat gastroesophageal reflux disease (GERD), diabetes, and sometimes to treat nausea in chemotherapy patientsOver-the-counter cough and cold medications that contain dextromethorphan (DXM) like Children's Robitussin Cough Long-Acting, Vicks DayQuil Cough, Vicks Formula 44 Custom Care Dry Cough, Zicam Cough MAX, and many othersErgot derivatives, including Ergomar (ergotamine) for migraines and Methergine (methylergonovine) for uterine bleeding after childbirthA muscle relaxant called Amrix (cyclobenzaprine)Buspirone, a medication that's prescribed for anxiety disorders Other substances and supplements that can contribute to serotonin syndrome include: St. John's WortIllicit and recreational drugs such as cocaine, amphetamines, ecstasy, and LSDL-tryptophan, an over-the-counter amino acid supplement that people use to quit smoking, for mental health disorders, and to help athletic performanceLithobid (lithium), a mood stabilizer that's often used to treat bipolar disorder All of these drugs and substances affect serotonin in some way. Some block nerve receptors; some block reuptake; some slow the breakdown of serotonin; and some increase the release of serotonin. Because so many medications can contribute to serotonin syndrome, it's essential that any doctors you see who prescribe you medication always know about all the over-the-counter and prescription medications and supplements you're currently taking. Drugs That Increase the Risk of Serotonin Syndrome Risk Factors Your risk of developing serotonin syndrome goes up under the following circumstances. You're Taking a New Medication or Dose If you just started taking a serotonergic medication or you had your dose increased, you should watch for signs of serotonin syndrome. Some people's bodies are naturally slower than others at metabolizing serotonin, and this isn't something you or your doctor will know until you are on a drug that boosts serotonin. Most cases of serotonin syndrome start within 24 hours after starting or increasing a serotonergic medication and the majority of those start within six hours. You're Switching to a New Medication If you're switching from an MAOI to another antidepressant or vice versa, be especially careful to follow your doctor's guidance. Almost all antidepressants contain a warning that you should wait for at least two weeks, and sometimes more, when you switch antidepressant types. One of the main reasons for this is the danger that having both types of drugs in your system can lead to serotonin syndrome. Prozac (fluoxetine), in particular, takes several weeks to be flushed out of your body. You're Taking More Than One Medication Taking more than one serotonergic medication, supplement, or substance at the same time increases your risk of serotonin syndrome. For instance, you're on Wellbutrin for depression and you take an Imitrex (sumatriptan) for a migraine or you're taking Zoloft (sertraline) and you treat a cold with DayQuil (dextromethorphan). Treatment Once you've been diagnosed with serotonin syndrome, the first line of treatment is to discontinue all serotonergic drugs. Treatment may also include the use of medications to relieve symptoms or hospitalization to stabilize your condition. Medication Benzodiazepines like Valium (diazepam) or Ativan (lorazepam) may be helpful to relieve any muscular symptoms, and you may need supportive treatment like oxygen and intravenous (IV) fluids and stabilization of vital signs. Drugs that specifically act against serotonin, called serotonin antagonists, can potentially be useful. For mild to moderate cases, your symptoms should subside within 24 to 72 hours once you've discontinued taking the serotonergic drug and you can expect to fully recover. Hospitalization If your symptoms are worrisome, your doctor may have you hospitalized until you're stabilized. In cases where you're exhibiting signs of severe serotonin syndrome, you'll likely need to be hospitalized in the intensive care unit (ICU) until all your symptoms are gone. For high fever, you may need to be sedated and given a medication that keeps you still (paralytic) to avoid any more damage to your muscles, in which case, you'll also have a breathing tube and ventilator. Was this page helpful? Thanks for your feedback! Dealing with racing thoughts? Always feeling tired? Our guide offers strategies to help you or your loved one live better with bipolar disorder. Sign up for our newsletter and get it free. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Volpi-Abadie J, Kaye AM, Kaye AD. Serotonin syndrome. Ochsner J. 2013;13(4):533-540. Foong AL, Grindrod KA, Patel T, Kellar J. Demystifying serotonin syndrome (or serotonin toxicity). Can Fam Physician. 2018;64(10):720-727. Renoir T. Selective serotonin reuptake inhibitor antidepressant treatment discontinuation syndrome: A review of the clinical evidence and the possible mechanisms involved. Front Pharmacol. 2013;4:45. doi:10.3389/fphar.2013.00045 Isbister GK, Buckley NA, Whyte IM. Serotonin toxicity: A practical approach to diagnosis and treatment. Med J Aust. 2007;187(6):361-365. Additional Reading Boyer EW. Serotonin Syndrome (Serotonin Toxicity). UpToDate. Updated March 12, 2018. Mayo Clinic Staff. Serotonin Syndrome. Mayo Clinic. Updated January 20, 2017. MedlinePlus. Serotonin Syndrome. The American Society of Health-System Pharmacists, Inc. National Institutes of Health. U.S. National Library of Medicine. Updated August 14, 2018.