Serotonin Syndrome

Serotonin is a vital chemical in the human body that is found in the central nervous system, platelets, and gastrointestinal tract. It acts as a neurotransmitter that is involved in some of the important brain functions. It is the serotonin level in the human body that regulates various functions, like, muscle contractions, appetite, sleep, mood variations, learning and memory. Any increase or decrease of serotonin from its normal levels will result in symptoms that can range from mild to severe. Serotonin syndrome is a condition caused by high levels of this chemical in the body.

What is Serotonin Syndrome

As mentioned above, this condition is caused by the accumulation of serotonin in the body. Even though, serotonin is essential for various bodily functions, too much of this chemical can be harmful. Serotonin syndrome causes include intake of certain drugs, particularly, antidepressants (used for elevating the serotonin levels in the body). However, in most cases, this condition is found to be a result of a combination of drugs, rather than the use of a single one. In other words, symptoms of this syndrome can occur, when a person consumes more than one drug meant for elevation of serotonin levels in the body.

In such cases, large amounts of serotonin will be released in the body, causing serotonin syndrome. The most common combination is migraine drugs and antidepressants. Both of these drugs cause release of serotonin in the body, causing an accumulation of the chemical. This condition can also be caused in people who take illicit drugs like cocaine and LSD. Excess use of some dietary supplements can cause this condition, especially, serotonin supplements. Herbs like, St John's wort, Syrian Rue, Panax ginseng, nutmeg, etc. are also associated with this condition.

Drug Intake and Serotonin Syndrome

As far as drugs are concerned, selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), anti migraine medicines, some pain killers, certain anti nausea drugs, lithium medication, some herbal supplements, serotonin supplements, antibiotics, etc. may singly or jointly contribute to serotonin syndrome. This condition may happen to a person, who takes antidepressant medication for the first time or after increasing the dosage of these drugs. It is also possible in those, who take more than one antidepressant drug. If the person who takes antidepressants regularly, consumes a migraine drug or any medication that can increase serotonin levels, then also, this syndrome can occur. FDA has recently instructed drug manufacturers to provide a warning in such medication.

Symptoms and Treatment

The symptoms of this syndrome may range from mild to severe. Sometimes, it can be life-threatening too. In most cases, symptoms will appear within minutes of ingestion of the drugs. Some of the common and mild symptoms are shivering, increased body temperature, sweating, dilated pupils, tremors, nausea, vomiting, and restlessness. Moderate serotonin syndrome symptoms include high body temperature, high blood pressure, mental confusion, agitation and tremors in the lower limbs. Severe and life-threatening symptoms are rapid and dangerous increase in blood pressure and heart rate, unconsciousness, heat stroke or hyperthermia and high body temperature (around 106 °F). These severe symptoms may lead to complications like coma, renal failure, rhabdomyolysis, etc.

Diagnosis of serotonin syndrome is done by close monitoring of the patient for some time. He/she may also be required to undergo certain tests to rule out the possibility of other medical conditions. In case of mild symptoms, the doctor may ask you to lower the dosage of antidepressant or to stop its use totally. In some cases, he may ask you to stop using other medication that are causing the symptoms, along with the antidepressant. Moderate to severe symptoms require hospitalization and treatment will be decided as per the severity of the condition. Commonly used drugs include serotonin inhibiting drugs for blocking the production of this chemical in the body, muscle relaxants and drugs to lower blood pressure and heart rate. The patient may also be administered with IV fluids and oxygen.

In short, serotonin syndrome can be a life-threatening condition for some people. While, severe symptoms require immediate medical attention, untreated minor symptoms may also get worse with time and may result into severe consequences. Once the treatment is started, the symptoms may disappear within 24 hours. In some cases, it will take longer for the symptoms to subside. So, if you are taking antidepressants, any other medication must be taken as per the instructions of your doctor. Even a change in the dosage of antidepressants should not be done without his/her consent.