New use for an old drug: oral ketamine for treatment-resistant depression.

Treatment-resistant depression (TRD) is a disabling disorder that can interfere with a patient's capacity to understand and participate in medical care and thus negatively impact individual morbidity and mortality. Hospitalised patients with TRD may require rapid alleviation of severe symptomatology, particularly when suicidal or if unable to participate in care decisions. Ketamine is well known for its anaesthetic effects and its use as a 'street' drug; however, its action as an N-methyl-D-aspartate receptor antagonist makes ketamine a potential therapy for TRD. The majority of studies investigating ketamine for TRD have used intravenous drug delivery, demonstrating benefit for rapid alleviation and sustained response of depression symptoms. Oral ketamine for urgent alleviation of TRD symptoms is less reported. We describe rapid alleviation of severe TRD with oral ketamine in a severely ill postoperative hospitalised patient, and review the current literature on 'off-label' use of ketamine for treatment of refractory depression. 2016 BMJ Publishing Group Ltd.