Background: To assess the response to ketamine in patients with difficult pain syndromes.
Methods: The charts of patients with uncontrolled pain despite opioid dose escalation of at least two opioids or a combination of them, selected for a burst of ketamine and midazolam were reviewed. One hundred mg/day of ketamine and midazolam 15 mg/day by a continuous intravenous infusion for about 48 hours was offered to patients.
Results: Forty-four patients received a burst of ketamine. Ten patients did not achieve any improvement. Pain intensity decreased from a mean of 7.8 (SD, 1.6) to 2.8 (SD, 1.3) (P<0.0005). The outcome was considered optimal, good, and mild in 24, 9, and 1 patients, respectively. Adverse effects attributable to ketamine did not have relevant intensity and no patient discontinued the treatment due to psychomimetic adverse effects.
Conclusions: This data suggests that a burst of ketamine and midazolam at low doses, may reverse an unfavourable opioid response, assisting the opioid switching. Although the role of ketamine remains controversial, it should not deter physicians to do not use that in specific conditions.
Keywords: Cancer pain; adverse effects; ketamine; palliative care; refractory pain.