Abstract
Purpose: Approximately 30% of patients with major depressive disorder (MDD) are treatment resistant. There is an unquestionable need for new treatment strategies. Subanesthetic doses of intravenous (IV) ketamine have a rapid antidepressant effect in treatment-resistant depression (TRD). This paper describes the efficacy of repeated series of intravenous ketamine infusions as an add-on treatment in five TRD inpatients.Methods: Eligible patients aged 43–63 were given eight ketamine infusions as an add-on treatment for patients with MDD. The subjects have readministered the intervention due to worsening depressive symptoms.Results: Of the five inpatients given ketamine as a series of eight infusions, one underwent three, and four had two treatment series. Four patients achieved remission after first series and three after the second series of ketamine infusions. The adverse reactions were mild and transient with no sequelae.Limitations: Presented case series applies to short-term intervention with IV ketamine as an add-on therapy. The results cannot be generalized to the long-term maintenance treatment nor other ketamine formulations as well as different administration schedules and dosing.Conclusions: This case series showed efficacy and safety of the repeated series of IV ketamine treatment in TRD in MDD and bipolar disorder type I. The subsequent interventions were safe and observed adverse events were mild and transient. Interestingly, the IV ketamine treatment at successive administrations seems to alter the major depression severity of the next affective episode. There is a critical need for further research regarding IV ketamine treatment effectiveness and long-term safety in future studies.
Highlights
The antidepressant effect of ketamine persists days or weeks beyond treatment, and the assumption may be that the rapid effect will appear, in subsequent ketamine treatment [1].There is evidence for ketamine use in treatment-resistant depression (TRD) in major depressive disorder (MDD) and bipolar disorder (BD)
Many studies confirmed the antidepressant effect of ketamine used in a single sub-anesthetic intravenous (IV) dose in patients with major depression and TRD patients [2, 3]
The worsening of depression may occur after infusions are completed, and there is a need for the development of new strategies to maintain the beneficial effects of ketamine treatment
Summary
The antidepressant effect of ketamine persists days or weeks beyond treatment, and the assumption may be that the rapid effect will appear, in subsequent ketamine treatment [1].There is evidence for ketamine use in treatment-resistant depression (TRD) in major depressive disorder (MDD) and bipolar disorder (BD). Current pharmacological treatments for depression prove unsatisfactory efficacy with a proportion of subjects demonstrating TRD The observation applies both to MDD and BD type I (BD I). Many studies confirmed the antidepressant effect of ketamine used in a single sub-anesthetic intravenous (IV) dose in patients with major depression and TRD patients [2, 3]. Subsequent studies confirmed this effect in repeated doses [4, 5], twice-weekly [3, 6, 7], and thriceweekly [8,9,10] administration schedules. This report presents the antidepressant effect of two and three repeated series of IV ketamine in TRD patients with MDD and BD I
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