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 | |||
published 2000