A recent systematic review of randomized controlled trials (RCTs) has investigated the efficacy of ketamine in reducing suicidal ideation (SI). The review included 16 studies, examining both racemic ketamine and its enantiomer, S-ketamine, administered intravenously (IV), intranasally (IN), or intramuscularly (IM).
The review found that IV ketamine and IV S-ketamine were associated with a reduction in SI in various patient populations, including those with major depressive disorder (MDD), treatment-resistant depression (TRD), and bipolar disorder. However, the duration of these effects varied depending on the frequency of administration. Single doses of IV ketamine typically showed a reduction in SI lasting up to 3 days, while multiple doses or infusions were associated with longer-lasting effects, extending up to 6 weeks.
The review also noted that the anti-SI effects of ketamine might be influenced by factors such as the presence of a history of suicide attempts, the duration of the current depressive episode, and the number of previous antidepressant treatment failures. However, these findings require further confirmation through additional independent studies.
Regarding the enantiomer R-ketamine, the review found limited evidence for its efficacy in reducing SI. While some studies suggested potential antidepressant effects of R-ketamine, further research is needed to determine its role in managing SI.
The review highlighted that most studies reported common adverse effects associated with ketamine, such as dissociation, dizziness, hypertension, and nausea. However, these effects were generally mild and subsided within the same day. The review also noted that ketamine was well-tolerated in most studies, with no serious incidents reported.
Overall, the review provides valuable insights into the potential of ketamine in reducing SI. However, further research is needed to clarify the optimal dosage, frequency of administration, and patient characteristics that may influence the effectiveness of ketamine in managing SI.