The toxicity of antidepressant poisoning: is it changing? A comparative study of cyclic and newer serotonin-specific antidepressants.
OBJECTIVE
To compare the clinical features of cyclic antidepressant and newer, non-cyclic, serotonin-specific antidepressant poisoning.


METHODS
Comparitive, descriptive study of all antidepressant overdose patients admitted to a hospital toxicology service from February 1997 to April 2001. Patient data were entered prospectively into a dedicated toxicology database for subsequent analysis.


RESULTS
There were 256 admissions for antidepressant poisoning (17.5% of all poisoning admissions). Cyclic antidepressant poisoning comprised 43% of antidepressant admissions. Statistically significant differences between the two groups included: cyclic antidepressant group had longer median length of stay (23.1 vs 15.9 h, P = 0.0008), greater need for endotracheal intubation (31%vs 4%, OR = 11.5, P < 0.0001) and higher incidence of seizures (7.2%vs 0.7%, OR = 10.4, P = 0.01), faster median pulse rate, longer QRS-interval on admission, and longer intensive care unit stays. However, non-cyclic, serotonin-specific antidepressant poisonings involved larger doses of antidepressants and were more likely to ingest other medications along with these. Serotonin syndrome was only seen in non-cyclic, serotonin-specific poisoning (10.3%, OR = 26.6, P = 0.0002). Patients with serotonin syndrome had a longer median hospital stay (46 vs 16 h, P < 0.0002) compared to other non-cyclic, serotonin-specific patients. There were no deaths during the study period.


CONCLUSIONS
Cyclic antidepressants still comprise a significant proportion of antidepressant poisoning and result in more significant morbidity than non-cyclic, serotonin-specific poisoning. Clinicians should also be aware that non-cyclic, serotonin-specific poisoning may result in the development of serotonin syndrome. This was the most significant toxic effect noted following non-cyclic, serotonin-specific poisoning in this study.
Graudins
Andis
A
Department of Emergency Medicine, Westmead Hospital, Hawkesbury Road, Westmead, NSW 2145, Australia. andis_graudins@wsahs.nsw.gov.au
Dowsett
Robert P
RP
Liddle
Christopher
C
D000293:Adolescent; D000328:Adult; D000929:Antidepressive Agents, Tricyclic / Q000506:poisoning*; D062787:Drug Overdose; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D008996:Monoamine Oxidase Inhibitors / Q000506:poisoning*; D009517:New South Wales; D011039:Poison Control Centers / Q000706:statistics & numerical data; D020230:Serotonin Syndrome / Q000453:epidemiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000506:poisoning*; D018709:Statistics, Nonparametric
D000929:Antidepressive Agents, Tricyclic; D008996:Monoamine Oxidase Inhibitors; D017367:Selective Serotonin Reuptake Inhibitors