Serotonin syndrome most commonly occurs after a dose increase (or overdose)of a potent serotonergic drug or shortly after a second drug is added. Some of the drugs involved have very long half-lives (e.g. fluoxetine) and may have been ceased weeks before.
Serotonin syndrome is diagnosed clinically and requires a thorough review of medications and a careful physical exam. Symptoms tend to develop rapidly after exposure to the precipitating drug: 30% within one hour, 60% within 6 hours, and nearly all patients with toxicity developing symptoms within 24 hours of exposure.
Serotonin syndrome is classically associated with a triad of symptoms: mental status changes, autonomic instability (i.e., tachycardia, hyperthermia, hypertension), and neuromuscular abnormalities (hyperreflexia, myoclonus). Unfortunately, not all patients present with such clear symptomology.
Cases of serotonin syndrome resulting in hospitalization or death are rare. Most cases do not require medication intervention, but can be managed by stopping the drug or decreasing the dose. Mild toxicity appears to be rare but is likely under-reported, unrecognized, or confused with other syndromes.
But too much serotonin causes signs and symptoms that can range from mild (shivering and diarrhea) to severe (muscle rigidity, fever and seizures).
Preventing Serotonin Syndrome
The best way to prevent serotonin syndrome is to let all of your caregivers know about all of your medications before adding any new ones. If you're on any drug that increases your serotonin level, check with your doctor before taking even an over-the-counter medication or supplement.
Serotonin syndrome occurs when someone has an excess of the neurotransmitter serotonin in their nervous system. The condition's symptoms generally fall into three categories: Altered mental status (irritability, agitation, restlessness, and anxiety)
In their review in The New England Journal of Medicine, Dr. Boyer and Dr. Shannon cited a report based on calls to poison control centers around the country in 2002 showing 7,349 cases of serotonin toxicity and 93 deaths. (In 2005, the last year for which statistics are available, 118 deaths were reported.)
If the symptoms came on rapidly (within a few hours), think serotonin syndrome. If they came on gradually, over days to weeks, think NMS. Fever, agitation/confusion, tachycardia, and muscle rigidity are almost universally present with NMS but can be present in varying degrees with serotonin syndrome.
Serotonin syndrome is a potentially serious condition that can occur when people take medications that boost serotonin levels. Most cases are mild and improve when a person stops taking the medication. Mild serotonin syndrome may cause subtle symptoms, such as mild tremors, restlessness, or headaches.
Combinations such as inducible or ocular myoclonus (uncontrollable eye movements) plus agitation or diaphoresis (unusual sweating), hypertonia (stiff muscles) with ocular or inducible clonus plus a temperature over 100 degrees Fahrenheit are also highly selective diagnosis criteria for serotonin syndrome and require ...
Mild elevation of serotonin levels causes mild serotonin toxicity and manifest as hyperreflexia, inducible clonus, tremors, anxiety, and restlessness. We hypothesize that mild SS may remain unnoticed for a longer duration and will manifest as insidious onset nonspecific symptoms.
The serotonin test measures the level of serotonin in the blood. Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Nonserotonergic antidepressants such as mirtazapine and bupropion are possible alternatives. Most tricyclic antidepressants (e.g., amitriptyline, desipramine and nortriptyline) are also less serotonergic than SSRIs, though clomipramine and imipramine are notable exceptions.
While serotonin syndrome typically resolves quickly, it can persist in some cases. Experts have explained that some medications have longer-lasting effects, which can cause serotonin syndrome to last for a few days, or in some cases, weeks.
Selective loss of Purkinje cells has previously been described in neuroleptic malignant syndrome and heatstroke, conditions that are characterized by hyperthermia. This suggests that hyperthermia may be a causative factor of brain damage in serotonin syndrome.
In severe cases, muscle rigidity may mask myoclonus and hyperreflexia. While uncommon, fatal cases of serotonin syndrome are associated with hyperthermia and seizure, the latter of which is often a preterminal event [16].
Patients with some anxiety disorders, including social anxiety, have been found to have higher, not lower, levels of serotonin. Some patients experience a temporary increase in anxiety when they begin SSRI and SNRI medications and serotonin levels go up.
Brain zaps are sensory disturbances that feel like electrical shock sensations in the brain. A person may also notice a brief buzzing sound and feel faint or black out momentarily. Brain zaps can happen when a person decreases or stops using certain medications, particularly antidepressants.
In the case of SSRIs, SNRIs, and related medications, the effects of taking antidepressants when not depressed can include developing a condition known as serotonin syndrome. Symptoms of this condition include the following: Confusion. Agitation.
Benzodiazepines, such as diazepam (Valium, Diastat) or lorazepam (Ativan), can help control agitation, seizures and muscle stiffness. Serotonin-production blocking agents. If other treatments aren't working, medications such as cyproheptadine can help by blocking serotonin production.
Most cases of serotonin syndrome are mild and may be treated by withdrawal of the offending agent and supportive care. Benzodiazepines may be used to treat agitation and tremor. Cyproheptadine may be used as an antidote.