Effects of ketamine medication on early and sustained PTSD symptoms

The NMDA receptor antagonist ketamine produces transient dissociative and psychotic states in healthy humans that resemble symptoms of posttraumatic stress disorder (PTSD). Thus, symptoms induced by severe stress or ketamine might both be related to altered glutamatergic neurotransmission. Since ketamine is used as an analgesic and sedative in emergency care, it might be one factor exacerbating PTSD in accident victims when given in the acute trauma phase. We performed two studies investigating the effect of a peritraumatic administered single or fractionated ketamine dose on PTSD symptoms assessed within 48h post-event (study 1) and approximately one year post-event (study 2) in moderately injured accident victims. In study 1 subjects (n=50) had received either racemic ketamine, opioids or no medication during emergency ambulance transportation. In study 2 patients (n=56) were treated with either (S)-ketamine, racemic ketamine or opioids. There were no differences between medication groups in regard to demographic variables, other traumatization, time between accident and investigation, injury severity and additional medication. Ketamine treated patients showed significantely increased PTSD symptoms in the early aftermath of the trauma (study 1) and (S)-ketamine but not racemic ketamine subjects exhibited strongly elevated symptoms even one year post-event (study 2). The data provide evidence for a modulating effect of ketamine on severity and duration of PTSD symptoms.