title: Metabolic correlates of theophylline therapy: a concentration-related phenomenon.
abstract: OBJECTIVE
  To determine the relationship of serum theophylline concentration with electrolyte and glucose abnormalities across a broad range of theophylline concentrations.
  
  
  METHODS
  Retrospective review of a computerized laboratory database between June 1, 1984 and June 1, 1986.
  
  
  METHODS
  A midwestern university medical center.
  
  
  METHODS
  Eight hundred sixty-nine patients with serum theophylline concentrations of > 5.5 mumol/L and a random unmatched sample (control group) of 350 in- and outpatient adults and children with no history of reactive airways disease or theophylline exposure.
  
  
  RESULTS
  Patients with measurable theophylline had a higher risk of hypokalemia, hyponatremia, hyperglycemia, hypophosphatemia, and hypomagnesemia compared with the unexposed control group. Unadjusted odds ratios (OR) were: (1) hypokalemia OR = 4.2 (95 percent CI 2.2 to 7.9); (2) hyponatremia OR = 5.4 (95 percent CI 2.0 to 12.9); (3) hypomagnesemia OR = 1.6 (95 percent CI 1.0 to 2.5); (4) hyperglycemia OR = 2.3 (95 percent CI 1.7 to 3.0); and (5) hypophosphatemia OR = 2.7 (95 percent CI 1.2 to 5.3). A linear concentration-response relationship was documented between serum theophylline concentration and all metabolic disturbances.
  
  
  CONCLUSIONS
  Measurable theophylline was associated with increased risk for glucose and electrolyte abnormalities in a concentration-related fashion across a broad range of theophylline concentrations from 5.5 to > or = 110 mumol/L.
authors.affiliation: Department of Medicine, University of Minnesota Medical School, Minneapolis 55455.
authors.forename: J M
authors.initials: JM
authors.lastname: Flack
authors.forename: K W
authors.initials: KW
authors.lastname: Ryder
authors.forename: D
authors.initials: D
authors.lastname: Strickland
authors.forename: R
authors.initials: R
authors.lastname: Whang
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D006943:Hyperglycemia / Q000097:blood; D007008:Hypokalemia / Q000097:blood; D007010:Hyponatremia / Q000097:blood; D017674:Hypophosphatemia / Q000097:blood; D008274:Magnesium / Q000097:blood; D008659:Metabolic Diseases / Q000097:blood*; D012189:Retrospective Studies; D012307:Risk Factors; D013806:Theophylline / Q000009:adverse effects / Q000097:blood* / Q000627:therapeutic use
chemical_list: D013806:Theophylline; D008274:Magnesium