Does Lidocaine Cause False Positive Results on Cocaine Urine Drug Screen?

BACKGROUND: Individuals who have tested positive for cocaine have claimed that lidocaine, or its primary metabolite, norlidocaine (monoethylglycinexylidide (MEGX)), have caused false positive results for the cocaine metabolite benzoylecgonine (BE) on urinary immunoassay testing. OBJECTIVE: The goal of the study was to determine if lidocaine exposure from routine medical procedures can result in false positives on a commercially available cocaine immunoassay urine drug screen (UDS). METHODS: We performed a cross-sectional observational study of patients receiving lidocaine as part of their regular care. Standard immunoassay drug screens and confirmatory liquid chromatography-mass spectrometry (LC-MS) were performed on all urine samples to assess for MEGX and BE. RESULTS: In total, 168 subjects were enrolled; 121 samples positive for lidocaine were ultimately included for analysis. One hundred fourteen of the 121 were also positive for MEGX. None of the 121 were positive for cocaine/BE on the UDS (95% CI), 0-3.7% for the full sample and 0-3.9% for the 114 who tested positive for MEGX. CONCLUSION: The present study found no evidence that lidocaine or norlidocaine are capable of producing false positive results on standard cocaine urine immunoassays.

Sitagliptin for prevention of stress hyperglycemia in patients without diabetes undergoing general surgery: A pilot randomized study.

AIM: We investigated if a dipeptidyl peptidase-4 inhibitor, sitagliptin, can prevent perioperative stress hyperglycemia in patients without prior history of diabetes mellitus undergoing general surgery. METHODS: This double-blind pilot trial randomized general surgery patients to receive sitagliptin (n = 44) or placebo (n = 36) once daily, starting one day prior to surgery and continued during the hospital stay. The primary outcome was occurrence of stress hyperglycemia, defined by blood glucose (BG) >140 mg/dL and >180 mg/dL after surgery. Secondary outcomes included: length-of-stay, ICU transfers, hypoglycemia, and hospital complications. RESULTS: BG >140 mg/dL was present in 44 (55%) of subjects following surgery. There were no differences in hyperglycemia between placebo and sitagliptin (56% vs. 55%, p = 0.93). BG >180 mg/dL was observed in 19% and 11% of patients treated with placebo and sitagliptin, respectively, p = 0.36. Both treatment groups had resulted in similar postoperative BG (148.9 ±â€¯29.4 mg/dL vs. 146.9 ±â€¯35.2 mg/dL, p = 0.73). There were no differences in length-of-stay (4 vs. 3 days, p = 0.84), ICU transfer (3% vs. 5%, p = 1.00), hypoglycemia <70 mg/dL (6% vs. 11%, p = 0.45), and complications (14% vs. 18%, p = 0.76). CONCLUSION: Preoperative treatment with sitagliptin did not prevent stress hyperglycemia or complications in individuals without diabetes undergoing surgery.