Ketamine in Treatment‑Refractory PTSD: Evidence‑Based Findings

Mechanism of Action

• Ketamine acts as a non‑competitive, open‑channel antagonist of NMDA receptors, blocking glutamate binding and thereby modulating excitatory neurotransmission in the central nervous system【1】.
• NMDA‑receptor antagonism initiates a downstream cascade that enhances AMPA‑receptor throughput, a process considered essential for the rapid therapeutic effects observed in PTSD and depression【1】.

Clinical Efficacy

• In adults with treatment‑refractory PTSD, a single intravenous infusion of ketamine 0.5 mg/kg over 40 minutes produces a rapid reduction in symptom severity within 24 hours, with benefits persisting for several days【2】.

Dose‑Dependent Considerations

• Sub‑anesthetic dosing (0.5 mg/kg over 40 minutes) yields therapeutic improvement with tolerable dissociative symptoms, whereas higher, anesthetic‑level doses may exacerbate PTSD symptoms through heightened psychomimetic effects【2】.

Adverse Effects – Psychotomimetic Profile

• At the 0.5 mg/kg infusion dose, transient psychotomimetic events occur in approximately 20 % of patients (hallucinations) and 12 % (nightmares); these effects typically resolve without intervention【3】.

Pharmacokinetics and Duration of Action

• Ketamine’s redistribution half‑life from the central nervous system is about 2.5 hours, yet the clinical antidepressant and anti‑PTSD effects can last 2–3 days after a single infusion, reflecting sustained neuroplastic changes【3】.

Respiratory and Cardiovascular Safety (Respiratory Focus)

• Unlike benzodiazepines and opioids, ketamine preserves respiratory drive and functions as a potent bronchodilator, offering a safer respiratory profile for patients with compromised airway function【4】.