Lidocaine Infusions for Chronic Pain in Children

Inclusion Criteria: 1. Diagnosed with a chronic pain condition (\> 3 months) other conventional medical therapies (anticonvulsants, tricyclics etc), have not been effective. 2. American Society of Anesthesiologists class 1 or 2 3. Age 8-18 years 4. Ability to understand and use the numeric rating scale to rate their pain and to understand and answer other questionnaires 5. Negative pregnancy test in participants of child-bearing potential (Females 12 years of age and older, or menarchal if under 12) Exclusion Criteria: 1. History of seizures 2. Known liver or renal disease 3. Patient taking strong CYP1A2 inducers or inhibitors (fluvoxamine, phenytoin, cimetidine, amiodarone) or beta blockers (propranolol, metoprolol, nadolol) 4. Allergy or sensitivity to lidocaine or other local anesthetic 5. Cardiac conduction anomalies (eg. Heart block, Wolff-Parkinson-White) 6. Serum electrolytes (potassium, sodium, magnesium or calcium) outside of reference ranges 7. Pregnancy Withdrawal Criteria 1. Patient or parent/guardian request 2. Refusal to have intravenous access and serum levels drawn 3. Inability to complete pain scores on the questionnaires (paper or electronic) at the first infusion and weekly for 2 weeks and at one month following infusion 4. Baseline free carnitine concentration \< 26 micromoles/L or total carnitine \< 32 micromoles/L (reference values from SickKids Department of Pediatric Laboratory Medicine "Guide to Laboratory Services")