Peripheral opioids in inflammatory pain.

Topically applied opioids have provided effective analgesia without adverse effects, including tolerance, in adult patients with painful inflammatory conditions. The presumed mechanism of action is by interaction with opioid receptors which are sited on sensory nerve terminals and which may be up-regulated in inflammation. The use of peripherally acting opioids has not been studied in paediatric patients. The use of topical morphine gel is reported in two children with epidermolysis bullosa, where acute inflammatory pain is a major symptom and where effective analgesia is a major clinical problem. The gel provided rapid reduction in pain scores in the patients and without any reported adverse effects or tolerance. A topical route of analgesia might be extremely beneficial for children with other painful skin lesions, including burns or post-surgical wounds, and further studies are now required.