Evaluation and use of opioid analgesics in pediatric cancer pain

Morphine is the preferred opioid analgesic in pediatric cancer pain due to extensive clinical experience with it, significant pharmacokinetic and pharmacodynamic data following oral and parenteral administration, global availability, and the development of controlled-release formulations. Randomized clinical trials are needed to fully evaluate the pharmacokinetics, dose equivalence, clinical efficacy, and safety of other opioid analgesics in cancer pain. Clinical trials are also needed to evaluate the efficacy and safety of adjuvant analgesics in children, including tricyclic antidepressants, anticonvulsants, and antiarrhythmics for neuropathic pain and corticosteroids and diphosphonates for bone pain. Unfortunately, the number of children with cancer pain and stable analgesic requirements is usually not large enough to support well-controlled clinical trials at a single institution. Consequently, multicentre and perhaps multinational efforts are necessary to fully evaluate opioid pharmacokinetics, pharmacodynamics, and dosage guidelines in children with cancer.