Ketamine can be administered in more than a dozen different ways for on-label and off-label indications. Oral ketamine, administered as a liquid repurposed from ketamine for injection, is one way in which ketamine is used to treat depression and chronic pain. Such repurposing may seem unorthodox but has been reported for at least the past 3 decades from many countries, including Canada, England, India, Israel, Japan, New Zealand, and the United States. Oral ketamine, thus administered, is noninvasive, and a safe and inexpensive option for medical practitioners who treat severe, suicidal, and/or treatment-resistant depression. It is safe because, when administered as a liquid in a glass of water or fruit juice, it can be sipped across 20-30 min; treatment-emergent dissociative, neurological, and other psychophysiological effects are thereby minimized. It is inexpensive because there are no costs associated with patented formulations, hospitalization, monitoring facilities, and additional personnel. Because of its simplicity, safety, and inexpensiveness, oral ketamine represents an opportunity for low-resource settings, especially in low- and middle-income countries. This article is intended to be a teaching article. It presents a brief theoretical background to the use of ketamine in the treatment of depression, justifies oral ketamine as an alternative to intranasal and intravenous routes of administration, explains clinical contexts in which the intervention can be used, and presents a detailed protocol for the use of oral ketamine. Matters considered are fitness for oral ketamine, consenting, facilities required, instructions on how to conduct the session, dosing, monitoring, ending the session, scheduling future sessions, continuation and maintenance therapy, domiciliary use, and many others. Drug interactions and concurrent medications are also discussed. This article is therefore a prescriber's guide to the use of oral racemic ketamine that could, it is hoped, make ketamine available in settings in which it is currently unavailable but needed.
