TABLE 4 Guidelines for therapeutic drug monitoring of tricyclic antidepressants

Class Concentration-efficacy Concentration-toxicity Recommendation
Tricyclic Antidepressants Established ranges for 4 TCAs For all TCAs (tertiary Measurement of
(TCAs) for efficacy in major amine>secondary amine), TCA plasma level at
depressive disorder: incidence and severity of least once during a course
Tertiary amines: nortriptyline: 50-150 ng/ml toxicity (delirium, seizures, of treatment with
amitriptyline desipramine: 100-160 ng/ml cardiac arrhythmias) increase these drugs after steady
doxepine amitripyline: 75-175 ng/ml as the plasma TCA level state concentration is
imipramine imipramine: 200-300 ng/ml exceeds the antidepressant achieved. No need for
trimipramine therapeutic range. For example, repeat measurement
the increase in relative risk for unless a change in
Secondary amines: Remission rates of 42%-70% delirium above 300 and 450 ng/ clinical status of the
desipramine in range versus 15%-29% ml was 13.7- and 37-fold, patient, a compliance
nortriptyline outside range. Thus the respectively concern, or a suspected
protriptyline likelihood of full antidepressant change in ability to
a response in 2- to 3- fold metabolize and
greater inside versus outside eliminate TCAs.
these optimal ranges

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published 2000