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

Abstract

Background Widespread prescription of antidepressants and their resulting role in serotonin syndrome (SS) are of great importance for clinical practice in the elderly. This study aims to investigate possible associations of antidepressant drug‐induced SS with related variables in these patients. Methods A total of 238 older adults using antidepressants were included. Patients who fulfilled the Hunter Serotonin Toxicity Criteria (HSTC) for SS were considered as the clinical groups (mild, moderate, or severe), and those who did not as the control group. We recorded all patients' demographic and clinical characteristics, including age, gender, comorbidity index, number of medications, daily equivalent dose of the relevant antidepressant according to fluoxetine per day, electrocardiogram test results, laboratory results, and management. Results The mean age of all patients was 75.4 ± 7.6 years and 63.4% were female. Sixty patients had SS, while 178 patients did not. There was a significant difference between those with and without SS in terms of gender, frequency of combination antidepressant therapy, and daily equivalent antidepressant dose (P < 0.05). The most common diagnostic findings in SS patients were tremor and hyperreflexia and 31.7% was mild, and moderate in 68.3% with higher median age and number of medications (P < 0.041). Antidepressants were discontinued in all patients regardless of severity, of whom 71.7% were treated with benzodiazepines and 36.7% with cyproheptadine. After adjusting for age and sex, association with use of SSRI + SNRI, use of any combination therapy, and daily equivalent dose remained significant. Conclusions The widespread single or combined use of antidepressants in older adults represents an increased clinical concern for SS and physicians should be aware of this drug‐related complication in older patients.

Serotonin Syndrome From the Complex Drug Interactions of Second-Generation Antipsychotics in Older Patients: Case Report and Literature Review

“…The syndrome is more commonly reported among elderly patients. In a recent study, 2 Erken et al found that 25.2% (60 out of 238 participants) of elderly patients taking antidepressants resulted in serotonin syndrome, and at least two-thirds (68.3%) of these patients showed potentially life-threatening symptoms. Women were twice as likely as men to have serotonin syndrome, with the most common diagnostic findings in these patients being tremor and hyperreflexia.…”

“…S-ketamine has the advantages of a stronger analgesic effect, fewer psychomotor side effects, a faster clearance rate, and fast recovery time than racemic ketamine. 2 The general reaction to intravenous injection of S-ketamine ranges from mild lightness or irritability to more obvious reactions like losing control, visual illusions, ideological disorders, or delusional thinking. 3 However, our latest network meta-analysis has shown the potential preventive effects of ketamine on cognitive impairment after surgeries.…”

“…Widespread prescription of serotonergic agents, especially antidepressants, to older adults has become a clinical concern. In a recent study, 2 researchers found that one-fourth of elderly patients taking antidepressants developed serotonin syndrome, whereas at least two-thirds of these patients showed potentially life-threatening symptoms. Ingestion of multiple drugs increases the risk of serotonin syndrome.…”

Serotonin syndrome controversies: A need for consensus

“…Only 0.09% of patients (4 out of 4538) had SS[ 19 ]. Erken et al [ 25 ] examined 234 elderly patients (over 60 years old) who were taking antidepressants and had been admitted to a geriatric department. Sixty patients (25%) fulfilled Hunter criteria for SS[ 25 ].…”

“…Erken et al [ 25 ] examined 234 elderly patients (over 60 years old) who were taking antidepressants and had been admitted to a geriatric department. Sixty patients (25%) fulfilled Hunter criteria for SS[ 25 ]. Di Salvo et al [ 27 ] studied 133 consecutive patients who were admitted to the psychiatric inpatient unit and were using at least one serotonergic medication.…”