Predictors of Major Toxicity after Theophylline Overdose

15 December 1993 | Volume 119 Issue 12 | Pages 1161-1167

Objective: To identify patients at high risk for major toxicity after theophylline intoxication who might benefit from early charcoal hemoperfusion.

Design: A 67-month prospective study.

Setting: Massachusetts Poison Control System.

Patients: 249 consecutive patients referred after theophylline intoxication (defined by a peak serum theophylline concentration 167 µmol/L [30 mg/L]).

Interventions: Uniform, protocol-directed management recommendations.

Main Outcome Measures: Identification of risk factors for major toxicity.

Results: 119 patients (48%) not receiving theophylline therapy had acute intoxication; among those receiving such therapy, 92 (37%) had theophylline intoxication because of chronic overmedication and 38 (15%) had acute intoxication. Major toxicity developed in 62 patients (25%); 13 patients (5%) died. Major toxicity was more common in patients with intoxication due to chronic overmedication than in those with acute intoxication who were not receiving theophylline therapy (49% compared with 10%, risk ratio, 4.85; 95% CI, 2.96 to 7.94), even though the former group had lower peak serum theophylline concentrations [283 µmol/L compared with 777 µmol/L, P = 0.001]. Logistic regression analysis identified two major factors associated with the development of major toxicity: 1) peak serum theophylline concentrations in cases of acute intoxication and 2) patient age in cases of chronic overmedication. Receiver-operating characteristic curve analysis indicated that major toxicity occurred in patients with a peak serum theophylline concentration of greater than 555 µmol/L (100 mg/L) after acute intoxication and in patients older than 60 years (regardless of peak serum theophylline concentration) after chronic overmedication.

Conclusions: Predictors for major toxicity after theophylline intoxication differ by type of overdose.

Author and Article Information

From Children's Hospital, Harvard Medical School, and The Massachusetts Poison Control System, Boston, Massachusetts.
Requests for Reprints: Michael Shannon, MD, MPH, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115.
Acknowledgments: The author thanks Dr. Frederick H. Lovejoy for assistance in manuscript preparation; Drs. Sam Lesko and Terry Fenton for assistance in statistical analyses; the poison specialists of the Massachusetts Poison Control System for their help in patient ascertainment; and Drs. Alan Woolf, Gary Fleisher, and Donald Goldmann for their helpful comments.