TRICYCLIC ANTIDEPRESSANT CONCENTRATIONS IN PLASMA - AN ESTIMATE OF THEIR SENSITIVITY AND SPECIFICITY AS A PREDICTOR OF RESPONSE

An analysis of the literature on tricyclic antidepressant level in blo od using receiver operating characteristics curves as the primary stat istical tool was performed. For nortriptyline, a significant curviline ar relationship between therapeutic response and nortriptyline was obs erved that ranged from 58 to 148 ng/ml. The sensitivity and specificit y for the nortriptyline therapeutic window were 78 and 61%, respective ly. The response rate within the therapeutic range was 66% versus 26% outside the therapeutic range. For desipramine, a significant linear r elationship between therapeutic response and desipramine concentration in plasma was observed. The threshold concentration in plasma for the rapeutic response was 116 ng/ml. The sensitivity and specificity for t he desipramine threshold level in blood were 81 and 59%, respectively. The response rate above the threshold level was 51% versus 15% below the therapeutic threshold concentration. For imipramine, a significant curvilinear relationship between therapeutic response and total imipr amine (imipramine + desipramine) concentration in plasma was observed between 175 and 350 ng/ml. The sensitivity and specificity for the tot al imipramine concentrations in plasma were 52 and 74%, respectively. The response rate within the therapeutic range was 67% versus 39% outs ide the therapeutic range. For amitriptyline, a significant curvilinea r relationship between therapeutic response and total amitriptyline (a mitriptyline + nortriptyline) concentration in plasma was observed bet ween 93 and 140 ng/ml. The sensitivity and specificity for the total i mipramine concentrations in plasma were 37 and 80%, respectively. The response rate within the therapeutic range was 50% versus 30% outside the therapeutic range.