Biweekly vs Triweekly low dose intravenous ketamine acute series for severe major depression: A case report

Background: One third of the patients with Major Depression Disorder (MDD) fail to respond to conventional antidepressant treatments - treatment resistant depression (TRD). Low-dose IV ketamine (LDIVK) treatment has become a promising solution for these patients. However, infusion regimens for LDIVK acute series have not been standardized yet. Also, evidence is scarce for retrialing LDIVK treatment to manage MDD symptom recurrences. Methods: This is a case study of a 45-year-old female experiencing MDD TRD, who completed a triweekly and a biweekly acute course (4 week) of LDIVK treatment three years apart. Treatment effectiveness was assessed by comparing baseline to weekly depression severity scores using validated psychiatric scales to determine changes in depression symptoms. Tolerability was assessed by systematically registering side effects through the infusions. Results: In both acute series, the patient achieved symptomatic response equivalent to remission. On the triweekly acute course the patient achieved symptom remission by the second week and in the biweekly acute course by the third week. Reported side effects were mild and transient. Limitations: Results of only one patient included in this report and a different number of LDIVK infusions in each acute course, with the triweekly vs biweekly course providing four additional infusions in four weeks. Conclusions: These results suggest that implementing a triweekly regimen may be well-tolerated and result in a faster treatment response in certain patients, compared to a biweekly regimen. Furthermore, this case also supports the possibility of a ketamine retrial in case of major depressive recurrences.