Acetaminophen Dosing in Obese Adolescents

Inclusion Criteria: * Participant will be a Children's National Health System (CNHS) inpatient or outpatient admitted for at least 24 hours observation as part of the surgical plan of care. * Age range will be between 10 and 18. * BMI% will be calculated using height and weight and will include the 5th-85th% (normal weight) and greater than or equal to 95th %.( obese weight) * ASA physical classification of I, II or III. * All racial and ethnic groups will be included Exclusion Criteria: * Any patient that is pregnant or lactating. * Renal insufficiency identified by GFR \<60 ml/min/1.73m2 and/or creatinine \> 3 times upper limit of normal values * Liver disease identified by : AST, ALT, γ-GT, bilirubin, albumin and AlkP and PT \> 3 times upper limit of normal values * Patients with Gilbert-Meulengracht Syndrome * Chronic alcohol intake or use of alcohol within last 72 hours * Patients who are treated with drugs know to effect CYP2E1(inhibition: dithiocarb and disulfiram. Induction: isoniazid) and UGT (UDP-glucuronyltransferases) (induction: estradiol-containing contraceptives, carbamazepine, phenobarbital, phenytoin, mesuximide, oxcarbazepine, rifampicin, primidone, atazanavir / ritonavir, lopinavir / ritonavir, olanzapine, retigabine , nevaripine, efavirenz, saquinavir, nelfinavir, lamotrigine, felbamate, zonisamide, bupropion. Inhibition: valproic acid) * Diabetes mellitus type II patients * Smoking * Acetaminophen intake up to 24 hours before enrollment. * Acetaminophe…