Tricyclic antidepressants in red cells and plasma: correlation with impaired intraventricular conduction in acute overdose.
OBJECTIVE
Tricyclic antidepressant levels in red blood cells and plasma in acute overdose and their association with cardiotoxicity were studied.


METHODS
This was a prospective study in 15 patients with acute tricyclic antidepressant overdose. Tricyclic antidepressant parent compounds and metabolites were measured in red blood cells and plasma, and tricyclic antidepressant levels were correlated with ECG indexes of toxicity.


RESULTS
Plasma levels of the parent compounds were higher than their red blood cell levels on admission (mean +/- SD, 691 +/- 409 and 337 +/- 220 ng/ml, respectively). Admission metabolite levels were higher in red blood cells than in plasma (264 +/- 180 and 190 +/- 164 ng/ml, respectively). QRS duration and the red blood cell levels of the metabolites were significantly correlated at the time of admission (r = 0.77, p < 0.01), as well as at 6 to 10 hours (r = 0.74, p < 0.01).


CONCLUSIONS
In acute overdose, a shift of tricyclic antidepressants from plasma to red blood cells and increased levels of red blood cell metabolites reflect tissue redistribution of the drug. Tricyclic antidepressant red blood cell metabolites are the best markers for impaired intraventricular conduction.
Amitai
Y
Y
Department of Pharmacology, Rush-Presbyterian St. Luke's Medical Center, Rush University, Chicago, IL 60612.
Erickson
T
T
Kennedy
E J
EJ
Leikin
J B
JB
Hryhorczuk
D O
DO
Noble
J
J
Hanashiro
P K
PK
Frischer
H
H
D000293:Adolescent; D000328:Adult; D000929:Antidepressive Agents, Tricyclic / Q000097:blood* / Q000493:pharmacokinetics / Q000506:poisoning; D062787:Drug Overdose; D004562:Electrocardiography / Q000187:drug effects; D004912:Erythrocytes / Q000378:metabolism*; D006329:Heart Conduction System / Q000187:drug effects*; D006331:Heart Diseases / Q000097:blood* / Q000139:chemically induced; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies
D000929:Antidepressive Agents, Tricyclic