Use of ketamine in treatment-resistant depression: a systematic review

ABSTRACT Objective Ketamine presents itself as a promising alternative against treatment-resistant depression (TRD), however, the knowledge of its application as an antidepressant is still restricted. Therefore, the objective was to investigate its effectiveness in patients with TRD. Methods The literature search was carried out in the MedLine database. Inclusion criteria were: controlled and randomized clinical studies from the last five years and in English. We excluded articles that did not answer the PICO question and those with different sample size and study methodology, when compared to the tests that based this review. Results Considering a final sample of six articles, a better response to ketamine was observed (mainly in mood gain), when compared to conventional treatment against TRD. With its first infusion, at a dose of 0.5 mg/kg, it was possible to notice its antidepressant effects. The maintenance of these effects seems to be achieved with the administration of 0.5 mg/kg of the drug, three times a week. On the other hand, the reduction of such a dosage can diminish or cancel the effects. Conclusions The use of ketamine showed effective results improving the condition of TRD, with adverse effects of small severity and easy control. However, further studies, with larger samples and different methods, are needed, for a more consistent conclusion.