Amitriptyline overdose: clinical effects on tricyclic antidepressant plasma levels.

Tricyclic antidepressant (TCA) plasma levels after amitriptyline overdose were reviewed in a retrospective study. Amount of drug taken correlated with total TCA levels. Plasma concentrations were higher in blacks than whites, but no association could be found between TCA levels and age or sex of patients. History of routine use of amitriptyline at the time of overdose did not predict TCA levels, but the one fatality could be shown on the basis of previous steady-state levels to be a slow metabolizer. Serious overdoses as documented by high plasma TCA levels were seen in all major diagnostic groups.