Reactions 899 - 27 Apr 2002

SCitalopram/fluoxetine

Serotonin syndrome presenting as coma: casereport

A 35-year-old woman became comatose due to serotoninsyndrome during treatment with fluoxetine, and then againduring treatment with citalopram.

The woman, who was also receiving guaifenesin/pseudoephedrine, received fluoxetine 20 mg/day afterpresenting with symptoms of anxiety and insomnia. Shesubsequently reported mild tremors. Approximately 2 monthsafter starting fluoxetine, she became restless and thencollapsed after consuming ‘a few’ alcoholic beverages. Shewas flaccid and unresponsive, and she then became apnoeic.Resuscitative efforts for approximately 1 hour restoredspontaneous respiration, but she remained comatose for afurther hour. She was observed until the morning and thendischarged.

Following the episode, the woman experienced diffuseaching of her muscles. Fluoxetine was withheld for 1 weekafter the event, and then restarted. She stopped all alcoholintake. Approximately 3 weeks later, she felt nauseous, andthat evening was found in an unresponsive state. 30 minuteslater, she became apnoeic. She was ventilated for 2 hoursbefore she resumed spontaneous respiration. She receivedoxygen and IV dextrose overnight, but remained comatoseuntil the following evening. Fluoxetine was stopped. Sheexperienced diffuse muscular pain and weakness after theevent, which was alleviated with magnesium and pyridoxine[vitamin B6] over the next 2 months.

About 14 months later, the woman received gabapentin forinsomnia, but this agent was temporally associated with thedevelopment of severe abdominal symptoms and wasdiscontinued. Ten months later, she started citalopram 10mg/day. Three days later, she experienced shakiness,tremulousness and palpitations after consuming 6 beer, andshe became unresponsive and comatose. Neurologicalfindings were identical to those evident during her episodes offluoxetine-associated coma. Apnoea did not develop, and astep-wise recovery ensued after 3 hours. Her citalopramdosage was reduced to 5 mg/day. However, 3 days later, sheexperienced another episode of unresponsiveness and coma,without apnoea, lasting for 1.5 hours. Citalopram wasstopped. She did not receive any further medications thatincrease serotonin activity and she had not experienced anyfurther episodes of coma at follow-up approximately 10months later.

Author comment: ‘This case report demonstrates that whenan SSRI [selective serotonin reuptake inhibitor] is the identifiedculprit in causing serotonin syndrome, it is best to avoid allSSRIs and possibly all serotonergic medications.’Chechani V. Serotonin syndrome presenting as hypotonic coma and apnea:potentially fatal complications of selective serotonin receptor inhibitor therapy.Critical Care Medicine 30: 473-476, Feb 2002 - USA 800903068

1

Reactions 27 Apr 2002 No. 8990114-9954/10/0899-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved