Open-label Prospective, Interventional Study Assessing Efficacy and Safety of Intramuscular Ketamine for Suicidal Ideation in a Tertiary Care Hospital

Background: This study evaluated intramuscular (IM) ketamine’s efficacy and safety for rapid suicidal ideation reduction, addressing the critical need for fast-acting interventions in resource-limited settings where intravenous (IV) options are impractical. Methods: We conducted a pre-post-interventional study of IM ketamine (0.5 mg/kg) over one year after approval of the institutional ethics committee. Adult patients with suicidal ideation, as measured by the six-point Montgomery–Åsberg Depression Rating Scale-Suicidal Ideation (MADRS-SI), were included if their MADRS-SI score was >4. Post-injection monitoring of suicidal ideation and adverse effects (A/E) was done after two hours and on Days 1, 3, 7, 14, 21, and 28. A repeat injection of the same dose was given only if the MADRS-SI score became > 4 again. The paired- T -test and repeated-measure ANOVA test were used for statistical analysis. Results: Thirty-eight patients (mean age: 36.3 years) participated, with 66% diagnosed with major depressive disorder and a mean MADRS-SI score of 5.31. At two hours post-injection, the MADRS-SI score decreased by 4.13 points (78% reduction), with 76% ( N = 29) of patients reporting no suicidal ideation (score 0–1). Of the 28 patients who completed a one-month follow-up, 89% ( N = 25) maintained a reduction in suicidal ideation (mean reduction: 4.75 points). A total of 64% ( N = 16) required only one injection, while 36% required multiple injections. Three patients did not recover even after six trials of ketamine. Among 21 patients who completed six months of follow-up, 8 (28%) patients had relapsed. A/E was reported in 87% of patients, with dizziness and sedation being the most common (57%). No serious or life-threatening adverse effects were noted. Conclusions: IM ketamine (0.5 mg/kg) is effective and safe for the rapid reduction of suicidal ideation.