Administration of Intrathecal Ketamine in the Treatment of Refractory Cancer Pain: A Case Series.

Objectives: Intrathecal opioids may not be effective for severe refractory pain associated with cancer. Intrathecal ketamine may be effective in reducing pain in these cases, however, there is legitimate concern regarding ketamine neurotoxicity. We present our experience using intrathecal ketamine in 17 consecutive patients in one clinic, as well as, a case report of one patient who received intrathecal ketamine for 36 wk.

Materials and methods: A retrospective case review included all patients treated with intrathecal ketamine at one center. The primary outcome was dosing required to change pain intensity and signs of neurotoxicity.

Results: Seventeen patients received intrathecal ketamine, data was available on 11. Mean ketamine concentration was 794 mcg/ml. Mean basal dose was 341 mcg/day. All 11 experienced pain reduction. One experienced auditory hallucinations.

Conclusion: This study provides more data supporting the safety and efficacy of intrathecal ketamine in this population. While neurotoxicity is a concern, our experience has been positive.