Opioid-induced respiratory depression in paediatrics: a review of case reports.

Opioids remain the cornerstone of modern-day pain treatment, also in the paediatric population. Opioid treatment is potentially life-threatening, although there are no numbers available on the incidence of opioid-induced respiratory depression (OIRD) in paediatrics. To get an indication of specific patterns in the development/causes of OIRD, we searched PubMed (May 2012) for all available case reports on OIRD in paediatrics, including patients 12 yr of age or younger who developed OIRD from an opioid given to them for a medical indication or due to transfer of an opioid from their mother in the perinatal setting, requiring naloxone, tracheal intubation, and/or resuscitation. Twenty-seven cases are described in 24 reports; of which, seven cases were fatal. In eight cases, OIRD was due to an iatrogenic overdose. Three distinct patterns in the remaining data set specifically related to OIRD include: (i) morphine administration in patients with renal impairment, causing accumulation of the active metabolite of morphine; (ii) codeine use in patients with CYP2D6 gene polymorphism associated with the ultra-rapid metabolizer phenotype, causing enhanced production of the morphine; and (iii) opioid use in patients after adenotonsillectomy for recurrent tonsillitis and/or obstructive sleep apnoea, where OIRD may be related to hypoxia-induced enhancement of OIRD. Despite the restrictions of this approach, our analysis does yield an important insight in the development of OIRD, with specific risk factors clearly present in the data.