Metabolic correlates of theophylline therapy: a concentration-related phenomenon.
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.
Flack
J M
JM
Department of Medicine, University of Minnesota Medical School, Minneapolis 55455.
Ryder
K W
KW
Strickland
D
D
Whang
R
R
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
D013806:Theophylline; D008274:Magnesium