Antidepressant-induced serotonin syndrome in older patients: a cross-sectional study

Serotonin syndrome controversies: A need for consensus

Serotonin syndrome (SS) is a drug-induced clinical syndrome resulting from increased serotonergic activity in the central nervous system. Although more than seven decades have passed since the first description of SS, it is still an enigma in terms of terminology, clinical features, etiology, pathophysiology, diagnostic criteria, and therapeutic measures. The majority of SS cases have previously been reported by toxicology or psychiatry centers, particularly in people with mental illness. However, serotonergic medications are used for a variety of conditions other than mental illness. Serotonergic properties have been discovered in several new drugs, including over-the-counter medications. These days, cases are reported in non-toxicology centers, such as perioperative settings, neurology clinics, cardiology settings, gynecology settings, and pediatric clinics. Overdoses or poisonings of serotonergic agents constituted the majority of the cases observed in toxicology or psychiatry centers. Overdose or poisoning of serotonergic drugs is uncommon in other clinical settings. Patients may develop SS at therapeutic dosages. Moreover, these patients may continue to use serotonergic medications even if they develop mild to moderate SS due to several reasons. Thus, the clinical presentation (onset, severity, and clinical features) in such instances may not exactly match what toxicologists or psychiatrists observe in their respective settings. They produce considerable diversity in many aspects of SS. However, other experts discount these new developments in SS. Since SS is a potentially lethal illness, consensus is required on several concerns related to SS.

Cyproheptadine in serotonin syndrome: A retrospective study

Objective

Serotonin syndrome (SS) is an iatrogenic life-threatening condition caused by serotonergic agents. The treatment for SS involves the administration of a serotonin antagonist (cyproheptadine). However, the dosing schedule for cyproheptadine is not uniform in the literature.

Methods

We retrospectively evaluated 23 adult patients (>18 years) admitted to the Neurology Department and met the Hunter criteria for SS.

Results

The mean age was 35.2 years, and 52% were female. Ten patients were managed in the intensive care unit (ICU), whereas thirteen patients were admitted to the ward. Hyperreflexia was the most common clinical feature (100%), followed by clonus (91%), tachycardia (83%), and tremor (83%). Other common clinical features were rigidity (65%), increased bowel sound (61%), diaphoresis (48%), fever (43%), hypertension (39%), and myoclonus (30%). All but one patient received two or more serotonergic drugs. Tramadol was the most common serotonergic agent (39%), followed by sodium valproate (21%), and amitriptyline (21%). Cyproheptadine was administered to all patients. All patients admitted in the ICU received a loading dose of 12 mg followed by 2 mg every 2 h for at least 24 h. All patients admitted to the ward were given 4 mg of cyproheptadine three times each day. Every patient showed at least some response to cyproheptadine within 24 h. The total doses of cyproheptadine and the length of treatment differed between patients.

Conclusion

Any response to cyproheptadine at a therapeutic dose within 24 h, even a partial one, could be a diagnostic indicator of the existence of SS.

Serotonin Toxicity in Older People

Serotonin toxicity, sometimes referred to as serotonin syndrome, results in a triad of clinical features that include autonomic signs, neuromuscular changes, and altered mental status, which may range from mild symptoms to fatal toxicity. As a result, serotonin toxicity is best thought of as a spectrum of symptoms rather than as a syndrome. Older patients may be at higher risk for serotonin toxicity because of the presence of drug-drug interactions as well as pharmacokinetic changes that occur with aging.