Investigating the effectiveness of oral ketamine on pain, mood and quality of life in treatment resistant chronic pain.

Introduction: Chronic pain is defined as pain lasting longer than 3 months. This often causes persistent emotional distress and functional disability that is refractory to conventional treatments. Emerging evidence suggests that oral Ketamine therapy may have a specific role in managing treatment-resistant chronic pain. This study aimed to assess the effectiveness of oral ketamine within a tertiary chronic pain management clinic.
Methods: This study was a clinic-based retrospective descriptive study of 79 patients with a broad range of chronic pain diagnoses and treated with oral ketamine over a period up to 12 years. Changes in pain, mood and quality of life (QoL) were assessed using a numerical pain severity score, the Brief Pain Inventory (BPI), the Public Health Questionnaire (PHQ-9) and American Chronic Pain Association Quality of Life (QoL) scale.
Results: 73 patients were accessible for follow-up (mean daily dose and treatment duration were 193.84 mg and 22.6 months respectively). Pain scores decreased ( p  < 0.0001) on both numerical scores (41.6% decrease) and BPI scoring (mean decrease 2.61). Mood improved ( p  < 0.0001) across both PHQ-9 and BPI measurements. Patients also reported less difficulty with daily activities and improved QoL. The most common adverse reaction was drowsiness (21.9%), with 30.1% reporting no adverse reactions from Ketamine.
Discussion: This work adds to the growing body of evidence that under the supervision of a pain specialist, oral ketamine therapy may be a safe, tolerable and effective treatment for chronic pain conditions which have not responded to other management options. Further research is required to produce a more accurate understanding of its chronic use.
Key Message: This real-world study shows that patients being treated with oral ketamine for chronic pain report decreased severity of pain, improved mood and increased quality of life across all conditions.
Competing Interests: KL has received previous funding from Medtronic Ltd not related to this research. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(© 2023 Al Mukhaizeem, Nasa, Waldron, McDaid, Gorman, Featherstone, Barry, Murphy, Gallagher, Nair, O'Connor, Kelly, O'Hora, Dolan, Mac Colgain, McGrath, Blouin, Roman, Gaffney, Roddy and Levins.)