Analgesic Effect in Children of Low-Dose Ketamine for Mucositis Treated by Patient-Controlled Analgesia With Morphine

Inclusion Criteria: Painful mucositis Child from 5 to 18 years. Presenting mucitis induced by chemotherapy or a conditioning of graft hematopoïetic. A pain not controlled by systematic paracetamol (10mg/kg/4h) or a the propacetamol (20mg/kg/4h). Not presenting a neurological or psychological difficulty at the use of the PCA or a EVA. First morphine amount going back to less 48h, and lass administration dating of more than 4h at the time of the beginning of the perfusion of Ketamine/placebo (EVA > 30 after stop morphine). Assent signed by the parents and each time possible by the child. Exclusion Criteria: The child was already included in the study. The age of psychomotor development is lower than 5 years Presence of a depression or a major depressive episode according to definition DSM IV. Hepatic or renal anomaly major (rank 3 or 4 of the scale of toxicity NCI CTC v2.0) Bilirubin>3N Gamma WP>3N SGOT or SGPT >5N Creatinin>3N