A single intravenous dose of ketamine (0.5 mg/kg) rapidly reduced posttraumatic stress disorder (PTSD) symptom severity more than the active placebo midazolam in patients with chronic PTSD. Twenty-four hours after infusion, the ketamine group showed a mean reduction of 12.7 points on the Impact of Event Scale-Revised compared to midazolam. Ketamine also lessened comorbid depressive symptoms and improved overall clinical presentation. The treatment was generally well tolerated without persistent dissociative symptoms. These results suggest ketamine may offer a novel pharmacologic approach for chronic PTSD, though replication is needed.
Ketamine given intravenously at 0.5 mg/kg over 40 minutes was safe and well tolerated in a large group of patients with treatment-resistant depression. Across 205 infusions in 97 participants, the antidepressant response rate was 67%. Only about 2% of infusions were stopped due to adverse effects, and the overall dropout rate was 3%. Common temporary side effects in the first four hours included drowsiness, dizziness, poor coordination, blurred vision, and feeling strange or unreal. About one third of participants had changes in blood pressure or heart rate. There were small but significant increases in psychotomimetic and dissociative symptoms, but no lasting psychotic effects, medical complications, or increased substance use among those followed long-term.