Signs and Symptoms of Too Much Serotonin

exhausted businessman sitting in front of computer
A businessman sitting at his desk with a headache. (Image: XiXinXing/XiXinXing/Getty Images)

Serotonin, sometimes referred to as the happiness hormone, is an important regulator of many bodily functions, including mood, gastrointestinal activity, heart rate and breathing. In depressed individuals, serotonin is typically too low, necessitating medication to raise serotonin to normal levels. However, taking too much of this medication or taking it in conjunction with certain other drugs can cause a different problem called serotonin syndrome, which is characterized by an excess of serotonin in the body and brain.

Mild Symptoms

Someone with too much serotonin may experience a variety of mild symptoms, including diarrhea, nausea, vomiting, headache and shivering. The affected individual may become agitated, restless, uncoordinated or confused. He may develop goose bumps and a rapid heart rate. The muscles may twitch and the pupils may dilate. He may sweat heavily and develop rapid changes in blood pressure.

Severe Symptoms

If the levels of serotonin become extremely high, even more pronounced and dangerous symptoms may occur. This can include a high fever and irregular heartbeat. In some cases, the person may fall unconscious or have a seizure. Serotonin syndrome can be fatal if left untreated once serious symptoms develop.

Cause

Serotonin syndrome can occur from an intentional or accidental overdose of an antidepressant medication such as a serotonin reuptake inhibitor, or SSRI. More commonly, these symptoms appear as a result of two combined medications, such as one antidepressant and one migraine medicine. Other medicines that can lead to an excess of serotonin, especially when combined with antidepressants, include over-the-counter cold medicines, illegal drugs, lithium, some pain medications, anti-nausea drugs, and some antibiotics or antiretrovirals. Serotonin syndrome will not be diagnosed unless at least three symptoms are present and the patient has taken a drug or combination of drugs known to cause it.

Reaction

Mild symptoms of too much serotonin can be treated simply by stopping the medication that is causing the problem. Severe symptoms of serotonin syndrome require immediate medical intervention. Anyone experiencing these symptoms should be taken to the emergency room. After being treated at the hospital, the doctor will generally require the patient to remain under observation for 24 hours.

Timing

Symptoms of too much serotonin often come on within a few minutes to a few hours of taking the responsible medication. It is more likely to occur the first time a patient uses a new medication. Symptoms typically disappear within 24 hours after the person stops taking the drugs that caused it. With some antidepressants, however, it may take up to a few weeks to clear the system and get rid of all symptoms.

REFERENCES & RESOURCES
Load comments
PARTNER & LICENSEE OF THE LIVESTRONG FOUNDATION

Copyright © 2019 Leaf Group Ltd. Use of this web site constitutes acceptance of the LIVESTRONG.COM Terms of Use, Privacy Policy and Copyright Policy. The material appearing on LIVESTRONG.COM is for educational use only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. LIVESTRONG is a registered trademark of the LIVESTRONG Foundation. The LIVESTRONG Foundation and LIVESTRONG.COM do not endorse any of the products or services that are advertised on the web site. Moreover, we do not select every advertiser or advertisement that appears on the web site-many of the advertisements are served by third party advertising companies.