Can Gradual Dose Titration of Ketamine for Management of Neuropathic Pain Prevent Psychotomimetic Effects in Patients With Advanced Cancer?

• Published in: American journal of hospice & palliative medicine 2013-08, Vol.30 (5), p.450-454
• Main Authors: Okamoto, Yoshiaki, Tsuneto, Satoru, Tanimukai, Hitoshi, Matsuda, Yoichi, Ohno, Yumiko, Tsugane, Mamiko, Uejima, Etsuko
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Analgesics - administration & dosage; Analgesics - adverse effects; Analgesics - therapeutic use; Child; Female; Humans; Infusions, Intravenous; Ketamine - administration & dosage; Ketamine - adverse effects; Ketamine - therapeutic use; Male; Middle Aged; Neoplasms - complications; Neuralgia - drug therapy; Nursing; Pain Management - methods; Pain Measurement; Psychoses, Substance-Induced - etiology; Psychoses, Substance-Induced - prevention & control; Retrospective Studies; Young Adult
• ISSN: 1049-9091; 1938-2715
• DOI: 10.1177/1049909112454325

Background: Ketamine is often used to manage neuropathic pain in patients with cancer. However, it occasionally causes psychotomimetic effects such as vivid dreams, nightmares, illusions, hallucinations, and altered body image. Objective: To examine whether gradual dose titration of ketamine for management of neuropathic pain prevents psychotomimetic effects in patients with advanced cancer. Methods: This was a retrospective chart review. We administered ketamine when neuropathic pain in patients with advanced cancer became refractory to opioids and oral adjuvant analgesics. The starting dose of ketamine was 10 mg/d by continuous intravenous infusion. The dose was gradually increased by 10 mg/d every 4 to 6 hours to 50 mg/d or until the pain was relieved. It was subsequently increased by 25 mg/d every 12 to 24 hours until the pain was relieved. Results: For this study, we enrolled 46 patients with advanced cancer. The mean age was 52.2 ± 16.9 years. The mean dose at onset of action and maximum dose of ketamine were 56 ± 58 and 272 ± 214 mg/d, respectively. The mean pain intensity (numerical rating scale) decreased significantly from 7.3 ± 2.0 to 3.5 ± 2.2 after the administration of ketamine (P < .01). The effectiveness was 69.5%. No psychotomimetic effect of less than 300 mg/d was observed during the introduction phase even though psychotropic drugs were not prescribed. Mild sedation was observed in 3 patients (7%) as the only adverse effect during the introduction phase. Conclusion: Gradual dose titration of ketamine for management of neuropathic pain can prevent psychotomimetic effects in patients with advanced cancer.