title: Coadministration of co-trimoxazole with sulfonylureas: hypoglycemia events and pattern of use.
abstract: BACKGROUND
  Coadministration of co-trimoxazole with sulfonylureas is reported to increase the risk of hypoglycemia.
  
  
  METHODS
  We identified a cohort of Medicare beneficiaries aged 66 years or older who took glyburide or glipizide for diabetes from a 5% national sample of Medicare Part D claims data in 2008 (n = 34,239). We tracked each participant's claims during 2008-2010 for a co-trimoxazole prescription and subsequent emergency room visits for hypoglycemia. Descriptive statistics and logistic regression modeling were used to evaluate hypoglycemia-related emergency room visits after coadministration of co-trimoxazole with sulfonylureas and its utilization patterns in older adults with diabetes.
  
  
  RESULTS
  Sulfonylureas users prescribed co-trimoxazole had a significant higher risk of emergency room visits for hypoglycemia, compared with those prescribed noninteracting antibiotics (odds ratio = 3.89, 95% confidence interval = 2.29-6.60 for glipizide and odds ratio = 3.78, 95% confidence interval = 1.81-7.90 for glyburide with co-trimoxazole, using amoxicillin as the reference). Co-trimoxazole was prescribed to 16.9% of those taking glyburide or glipizide during 2008-2010, varying from 4.0% to 35.9% across U.S. hospital referral regions. Patients with polypharmacy and with more prescribers were more likely to receive co-trimoxazole. Patients with an identifiable primary care physician had 20% lower odds of receiving a co-trimoxazole prescription. Hospital referral regions with more PCPs had lower rates of coadministration of the two drugs (r = -.26, p < 0.001).
  
  
  CONCLUSIONS
  Coadministration of co-trimoxazole with sulfonylureas is associated with increased risk of hypoglycemia, compared with noninteracting antibiotics. Such coadministration is prevalent among older diabetic patients in the United States, especially in patients without an identifiable primary care physician.
authors.affiliation: Sealy Center on Aging and Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston. altan@utmb.edu.
authors.forename: Alai
authors.initials: A
authors.lastname: Tan
authors.affiliation: Department of General Internal Medicine, University of Texas MD Anderson Cancer Center, Houston.
authors.forename: Holly M
authors.initials: HM
authors.lastname: Holmes
authors.affiliation: Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston.
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Kuo
authors.affiliation: Department of Internal Medicine-Geriatrics, University of Texas Medical Branch, Galveston.
authors.forename: Mukaila A
authors.initials: MA
authors.lastname: Raji
authors.affiliation: Sealy Center on Aging and Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston. Department of Internal Medicine-Geriatrics, University of Texas Medical Branch, Galveston.
authors.forename: James S
authors.initials: JS
authors.lastname: Goodwin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000009:adverse effects*; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000188:drug therapy* / Q000453:epidemiology; D004347:Drug Interactions; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D005913:Glipizide / Q000008:administration & dosage / Q000009:adverse effects; D005905:Glyburide / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced* / Q000453:epidemiology; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D006278:Medicare; D019338:Polypharmacy; D011320:Primary Health Care; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000008:administration & dosage / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
chemical_list: D000890:Anti-Infective Agents; D007004:Hypoglycemic Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D005905:Glyburide; D005913:Glipizide
keywords: Diabetes; Drug–drug interaction; Hypoglycemia; Medicare; Older adults.