Several studies have shown that ketamine, an antagonist of NMDA receptors, represents a promising alternative in the treatment of depression. The therapeutic use of ketamine, commonly used at a dose of 0.5 mg/kg, and in a single application IV has been short and requires monitoring in a hospital setting. IM use has been shown to be effective in treating depression and suicide risk, and have low side effect profile.

Two patients diagnosed with bipolar depression and suicide risk were submitted to ketamine IM application (0.75 mg/kg), receiving one application of ketamine IM every two days, totaling 4 applications. Patients were under medical monitoring for 2 hours after injection verifying vital signs and potential side effects. Responses were measured using BDI, BAI and BSI.

To evaluate response of ketamine IM injections on depressive, suicidal and anxious symptoms.

Case 1: female, 20 years old, single with three recent suicide attempts, symptomatic for two months. Started lithium 450 mg daily. Side effects of ketamine were nausea, drowsiness and paresthesia. Case 2: female, 24 years old, single with symptoms lasting for six years. Started aripiprazole 5–10 mg and 25 mg lamotrigine concomitantly. Side effects of dry mouth, dizziness and dissociation.

The use of ketamine IM showed reduction of 75.5%–83.3%–85.7% (case 1) and 71.4%–77.2%–60.8% (case 2) in BDI, BAI and BSI, respectively as well as safety and tolerability in use.

The authors have not supplied their declaration of competing interest.