title: Direct Evidence of Acetaminophen Interference with Subcutaneous Glucose Sensing in Humans: A Pilot Study.
abstract: BACKGROUND
  Recent advances in accuracy and reliability of continuous glucose monitoring (CGM) devices have focused renewed interest on the use of such technology for therapeutic dosing of insulin without the need for independent confirmatory blood glucose meter measurements. An important issue that remains is the susceptibility of CGM devices to erroneous readings in the presence of common pharmacologic interferences. We report on a new method of assessing CGM sensor error to pharmacologic interferences using the example of oral administration of acetaminophen.
  
  
  METHODS
  We examined the responses of several different Food and Drug Administration-approved and commercially available CGM systems (Dexcom [San Diego, CA] Seven(®) Plus™, Medtronic Diabetes [Northridge, CA] Guardian(®), and Dexcom G4(®) Platinum) to oral acetaminophen in 10 healthy volunteers without diabetes. Microdialysis catheters were placed in the abdominal subcutaneous tissue. Blood and microdialysate samples were collected periodically and analyzed for glucose and acetaminophen concentrations before and after oral ingestion of 1 g of acetaminophen. We compared the response of CGM sensors with the measured acetaminophen concentrations in the blood and interstitial fluid.
  
  
  RESULTS
  Although plasma glucose concentrations remained constant at approximately 90 mg/dL (approximately 5 mM) throughout the study, CGM glucose measurements varied between approximately 85 to 400 mg/dL (from approximately 5 to 22 mM) due to interference from the acetaminophen. The temporal profile of CGM interference followed acetaminophen concentrations measured in interstitial fluid (ISF).
  
  
  CONCLUSIONS
  This is the first direct measurement of ISF concentrations of putative CGM interferences with simultaneous measurements of CGM performance in the presence of the interferences. The observed interference with glucose measurements in the tested CGM devices coincided temporally with appearance of acetaminophen in the ISF. The method applied here can be used to determine the susceptibility of current and future CGM systems to interference from acetaminophen or other exogenous pharmacologic agents.
authors.affiliation: 1 Endocrine Research Unit, Saint Mary's Hospital , Mayo Clinic, Rochester, Minnesota.
authors.forename: Ananda
authors.initials: A
authors.lastname: Basu
authors.affiliation: 1 Endocrine Research Unit, Saint Mary's Hospital , Mayo Clinic, Rochester, Minnesota.
authors.forename: Sona
authors.initials: S
authors.lastname: Veettil
authors.affiliation: 2 Immunochemical Core Laboratory, Mayo Clinic , Rochester, Minnesota.
authors.forename: Roy
authors.initials: R
authors.lastname: Dyer
authors.affiliation: 3 Automated Glucose Control LLC , Palo Alto, California.
authors.forename: Thomas
authors.initials: T
authors.lastname: Peyser
authors.affiliation: 1 Endocrine Research Unit, Saint Mary's Hospital , Mayo Clinic, Rochester, Minnesota.
authors.forename: Rita
authors.initials: R
authors.lastname: Basu
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood; D001786:Blood Glucose / Q000032:analysis* / Q000187:drug effects*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation* / Q000379:methods; D000068598:Data Accuracy; D004347:Drug Interactions; D045604:Extracellular Fluid / Q000737:chemistry; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects
chemical_list: D018712:Analgesics, Non-Narcotic; D001786:Blood Glucose; D000082:Acetaminophen