Serotonin Syndrome: What Clinicians Need to Know

Often, physicians think of serotonin only in terms of what happens when patients are lacking the neurotransmitter in sufficient amounts. However, in rare cases, patients may experience a condition known as Serotonin Syndrome, an ailment that results from an overabundance of serotonin in the body.

But why is it important to discuss this rare condition in the age of COVID-19 and other prevalent diseases?

We felt the need to highlight Serotonin Syndrome because it is frequently caused by an interaction between medications. Specifically, an interaction between ingredients found in many cough suppressants and those found in popular antidepressant medications..

A considerable number of patients routinely take antidepressants. Further, many of these individuals may also contract a respiratory disease and seek medication to treat it. Without due diligence on behalf of both the prescribing physician and the patient, Serotonin Syndrome could result.

In this article, I will attempt to provide an overview of this condition so that physicians are aware of the signs, symptoms, and causes of, as well as the treatment of Serotonin Syndrome.

Signs and Symptoms of Serotonin Syndrome

Serotonin Syndrome can result in signs and symptoms ranging from relatively mild to life-threatening. When Serotonin Syndrome is suspected, patients may experience any of the following:

• Incoherent speech
• Sudden loss of bowel and bladder control
• High body temperature
• Seizures

You can find a complete list of signs and symptoms on the Mayo Clinic website.

Unfortunately, these symptoms are relatively common in many conditions, often leading to a misdiagnosis if the physician is unaware of Serotonin Syndrome.

Common Causes of Serotonin Syndrome

Except in some extremely rare cases, Serotonin Syndrome is caused almost exclusively by an adverse drug interaction. Most commonly, Serotonergic Drugs, such as SSRIs (Selective Serotonin Reuptake Inhibitors) interact with cough medications containing dextromethorphan, a second serotonergic agent, to produce dangerous serotonin levels in a patient’s system.

If a single physician manages all of a patient’s medications and monitors any potential interaction, she may be able to catch this issue before it causes any problems.

However, due to:

• Multiple specialists treating one patient with sometimes spotty coordination,
• Exponentially more patients taking antidepressants,
• Unfamiliarity with the diagnosis of Serotonin Syndrome across the medical community,

This condition seems to be on the rise.

Treatment for Serotonin Syndrome

First and foremost, physicians need to make an accurate diagnosis of Serotonin Syndrome. This is perhaps the most challenging aspect of managing Serotonin Syndrome, especially in emergency situations where questioning the patient about prescription and non-prescription drug use may be impossible.

One diagnostic method is the Hunter Serotonin Toxicity Criteria, which seeks to determine the level of Serotonin present in the patient’s system. There are also other diagnostic criteria, each having its benefits and flaws. Ultimately, diagnosing Serotonin Syndrome involves ruling out all other likely causes of the observed symptoms.

Once the physician has determined that the patient is most likely suffering from Serotonin Syndrome, treatment can begin.

In mild cases, simply managing the patient’s vitals while restricting the medications that caused the symptoms will often resolve the issue. However, sometimes drugs known as serotonin antagonists may be indicated in more severe cases (an example being cyproheptadine).

An Ounce of Prevention…

As with nearly every issue, the best way to treat and manage Serotonin Syndrome is to prevent it.

Physicians who have familiarity with the condition and know to consider it within their differential diagnosis will have a much easier time treating the patient.

Likewise, physicians who perform a thorough medical history will recognize when patients are on certain drugs that may interact with one another, leading to Serotonin Syndrome.

Although most patients will recover from serotonin syndrome after a few days of hospitalization, the condition still poses high risks.

Therefore, before recommending certain cough syrups or medications to patients, it’s vital that physicians review current medications and ensure that no interactions will put the patient at risk for an adverse event.