[Pattern of usage of new antidepressants in clinical practice]

Data from naturalistic studies have reported differences in the clinical use of antidepressants referring to the need for adjusting doses, treatment duration, tolerability and use of concomitant medication. These differences could be considered as an indicator of the effectiveness of antidepressants in clinical practice settings.

It is a naturalistic, retrospective, observational study which objective is to evaluate and compare the pattern of antidepressant use (fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine) and to establish if there is a relation between the different pattern of use and the effectiveness of them.

A retrospective dataset of patients who initiated therapy on fluoxetine, fluvoxamine, paroxetine, sertraline, or venlafaxine with a follow-up period of 6 months was used. Information about clinical characteristics of patients and antidepressant pattern of use were collected. Pattern of antidepressant use were defined as: "initial doses", "upward dose titration", "augmentation strategy", "switching" and "early interruption of treatment". The efficacy of the therapy was assessed by the CGI-improvement.

Fluoxetine was the antidepressant more associated with a statistical significance (p = 0.001) to an stable pattern of use (initial doses without upward dose titration, switching or augmentation). After controlling for other observed baseline characteristics, patients who remained on their initial antidepressant therapy, with a stable pattern of use were 1.61 times more likely than patients who had an adjustment to therapy to experience a treatment response. Patients who initiated treatment with sertraline or venlafaxine were 2.155 and 4.831 times less likely, respectively, to experience a response relative to patients who initiated therapy on fluoxetine.

The need to upward dose titration, switching or augmentation in the treatment could be indicated a worse therapeutic control of the symptoms. Patients treated with fluoxetine are in a stable pattern of use more likely than patients in the other antidepressants, this fact is related with better global therapeutic results.