Pharmacokinetics of Acetaminophen in Morbidly Obese Patients

Inclusion criteria for morbidly obese patients: * BMI \> 40 kg/m2 undergoing bariatric surgery. * Patients between 18 - 60 years old * ASA physical classification of II or III * All racial and ethnic groups will be included Inclusion criteria for control group: * BMI between 18 and 25 kg/m2 undergoing general surgery * Patients between 18 - 60 years old * ASA (American Society of Anesthesiology) physical classification of I, II or III * All racial and ethnic groups will be included Exclusion criteria for all study arms: * Renal insufficiency * Liver disease * Patients with Gilbert-Meulengracht syndrome * Chronic alcohol intake or use of alcohol within last 72 hours * Pregnancy or breastfeeding * Patients who are treated with drugs know to affect CYP2E1 and UGT (UDP glucuronosyltransferase) * Diabetes mellitus type II patients * Smoking * Acetaminophen intake before the study (24 hours before study)