In children with advanced stages of cancer, pain control remains inadequate in many patients and a solution to this problem is sorely lacking. Factors related to progression of the primary disease and side-effects of high doses of opioids, the mainstay of pain therapy, contribute to the inadequacy of pain control. In addition, few studies suggest that opioids, by inducing tolerance, having pronociceptive effects and producing hyperalgesia in some patients, can also contribute to inadequacy of pain control. Researchers have shown that N-methyl-D-aspartate (NMDA) receptor antagonists may have a role in mitigating opioid-induced tolerance and hyperalgesia in adults. However, literature on NMDA antagonists to treat cancer pain in children and adolescents is scarce. We used subanesthetic doses of ketamine to treat 11 children and adolescents who were on high doses of opioids and yet had uncontrolled cancer pain. A low-dose ketamine infusion was administered to all patients to modulate the need for rapidly escalating opioid therapy. We found that in 8 of 11 patients, ketamine infusions used as an adjuvant to opioid analgesia was associated with opioid-sparing effects and apparent improvement in pain control and in the children's ability to interact with their family. This study suggests that infusions of ketamine may offer a promising therapeutic option in the treatment of appropriately selected children and adolescents with intractable cancer pain.
Perspective: In many children with advanced stages of cancer, pain control remains inadequate. We used subanesthetic doses of ketamine to treat 11 children and adolescents who were on high doses of opioids and had uncontrolled cancer pain. In the majority of patients, ketamine appeared to improve pain control and to have an opioid-sparing effect.