Pharmacogenetics of Ketamine in Children

Overview

The need to treat the children with painful diagnostic-therapeutic procedures has increased in the last years. There is evidence from a wide scientific literature that drugs available in the setting of procedural sedation and analgesia such as midazolam, fentanyl, nitrous oxide, ketamine and propofol are absolutely safe without a significant incidence of adverse effects, if administered by anaesthesiologists and also trained pediatricians outside the operating room. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that blocks glutamate excitatory effects. Ketamine's molecular mechanism is not restricted to the NMDA receptor. Several studies indicate interactions with a series of receptor systems, including opioid, cholinergic and dopaminergic receptors. Ketamine is a safe and effective drug during procedural analgesia and sedation applied to children outside the operating room. A recent multicenter study, showed that ketamine, without being associated with other analgesic or sedative drugs, is the drug regimen with the lowest risk of adverse effects during this procedures. Even though being safe, ketamine may cause some adverse effects. When ketamine is administered for procedural sedation outside the operating room, adverse effects more frequently recorded are emesis and recovery agitation, each with a prevalence of around 8%. Recovery agitation, defined as any abnormal behavioural response such as any combination of agitation, crying, hallucinations or nightmares after sedation, in some cases (around 1%) may be severe and leads to specific treatment, mainly benzodiazepines. Emesis and recovery agitation are minor adverse events, but both may be very unpleasant for the patient and may play a role in the perception of patients and their parents of the quality of sedation, especially in children who need repeated procedures. Identifying patients, particularly children with chronic illnesses and leukemia, at risk of emesis and recovery agitation may facilitate the choice of different drugs regimens, improving the quality of care. The aim of this study is the identification of genetic and epigenetic biomarkers useful to predict emesis and recovery agitation related to administration of ketamine for procedural sedation and analgesia applied to children and to correlate them with the pharmacokinetic profile.