Urinary serotonin level is associated with serotonin syndrome after moclobemide, sertraline, and citalopram overdose.
BACKGROUND
Altered mental status, autonomic dysfunction, and neuromuscular abnormalities are a characteristic triad of serotonin syndrome. No laboratory tests confirm the diagnosis of serotonin syndrome.


METHODS
A 35-year-old woman took moclobemide, sertraline, and citalopram in a suicide attempt. She was conscious with mild tachycardia, hypertension, and tachypnea one hour after ingestion. In the second hour after ingestion diaphoresis, mydriasis, horizontal nystagmus, trismus, hyperreflexia, clonus, and tremor appeared. She became agitated and unresponsive. In the third hour after ingestion she became comatose and hyperthermic. She was anesthetized, paralyzed, intubated, and ventilated for 24 hours. Serum moclobemide, sertraline, and citalopram levels were above therapeutic levels. The serum serotonin level was within normal limits and the urinary 5-hydroxyindoleacetic acid:creatinine ratio was below the average daily value. The urinary serotonin:creatinine ratio was increased on arrival (1 mg/g).


CONCLUSIONS
The urinary serotonin level is increased in serotonin syndrome due to a monoamine oxidase inhibitor and selective serotonin-reuptake inhibitors overdose. It is possible that urinary serotonin concentration could be used as a biochemical marker of serotonin syndrome.
Brvar
Miran
M
Poison Control Centre, University Medical Centre Ljubljana, Ljubljana, Slovenia. miran.brvar@kclj.si
Stajer
Dusan
D
Kozelj
Gordana
G
Osredkar
Josko
J
Mozina
Martin
M
Bunc
Matjaz
M
D000328:Adult; D000928:Antidepressive Agents / Q000506:poisoning; D015283:Citalopram / Q000506:poisoning*; D062787:Drug Overdose; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine; D020912:Moclobemide / Q000506:poisoning*; D008996:Monoamine Oxidase Inhibitors / Q000506:poisoning; D012701:Serotonin / Q000097:blood / Q000652:urine*; D020230:Serotonin Syndrome / Q000097:blood / Q000139:chemically induced* / Q000652:urine; D017367:Selective Serotonin Reuptake Inhibitors / Q000506:poisoning; D020280:Sertraline / Q000506:poisoning*; D013406:Suicide, Attempted
D000928:Antidepressive Agents; D015283:Citalopram; D006897:Hydroxyindoleacetic Acid; D020912:Moclobemide; D008996:Monoamine Oxidase Inhibitors; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline