title: An evaluation of hyperkalemia and serum creatinine elevation associated with different dosage levels of outpatient trimethoprim-sulfamethoxazole with and without concomitant medications.
abstract: BACKGROUND
  Adverse events associated with high-dose trimethoprim-sulfamethoxazole (TMP-SMX) for outpatient infections, particularly those likely caused by community-acquired methicillin-resistant Staphylococcus aureus, have not been adequately characterized.
  
  
  OBJECTIVE
  Describe hyperkalemia and acute renal injury associated with high-dose TMP-SMX.
  
  
  METHODS
  An electronic medical record database retrospective study was conducted of outpatients receiving high-dose or low-dose TMP-SMX, comparing the incidences of hyperkalemia and acute renal injury.
  
  
  RESULTS
  Of 6162 patients, more developed hyperkalemia (3.06% vs 1.05%, P < .0001) or acute renal injury (1.99% vs 0.700%, P = .0001) in the high-dose TMP-SMX group. Variables independently associated with hyperkalemia included age >58 years (odds ratio [OR] = 3.44; 95% CI = 1.86-7.0; P < .0001), concomitant receipt of an NSAID (OR = 1.71; 95% CI = 1.02-2.79; P = .044) or an ACE inhibitor (OR = 3.27; 95% CI = 2.06-5.14; P < .0001), high-dose TMP-SMX prescribed (OR = 2.92; 95% CI = 1.85-4.60; P < .0001), and baseline elevated serum creatinine (OR = 45.1; 95% CI = 21.7-93.2; P < .0001). Variables independently associated with acute renal injury included concomitant receipt of an ACE inhibitor (OR = 2.36; 95% CI = 1.01-5.24; P = .048) or a potassium supplement (OR = 4.10; 95% CI = 1.45-10.1; P = .010), high-dose TMP-SMX prescribed (OR = 3.70; 95% CI = 1.70-8.12; P = .0012), and baseline elevated serum creatinine (OR = 2110; 95% CI = 724-7980; P < .0001).
  
  
  CONCLUSIONS
  Serum creatinine and potassium concentrations should be monitored in outpatients receiving high-dose TMP-SMX.
authors.affiliation: Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
authors.forename: Chris A
authors.initials: CA
authors.lastname: Gentry
authors.forename: Ann T
authors.initials: AT
authors.lastname: Nguyen
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology; D015994:Incidence; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000900:Anti-Bacterial Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D003404:Creatinine; D011188:Potassium
keywords: hyperkalemia; renal insufficiency; trimethoprim-sulfamethoxazole