Poor tolerance of oral activated charcoal with theophylline overdose.

Vomiting is a common manifestation of theophylline toxicity and may limit the tolerance of orally administered activated charcoal (OAC). However, this potentially important interaction has received little attention. The records of 33 consecutive patients who presented to the emergency department with serum theophylline concentrations greater than 30 micrograms/ml and toxic symptoms and who were treated with OAC were reviewed. Seventeen (22%) of the 76 OAC doses were vomited. Six patients who had ingested theophylline as a single acute overdose vomited all 11 OAC doses administered, whereas 27 patients receiving chronic theophylline therapy vomited only six (11%) of 65 OAC doses. Vomited doses were associated with higher serum theophylline concentrations. Although theophylline-related vomiting preceded OAC intolerance in all acute toxicity patients, this condition was not predictive of OAC vomiting for chronic toxicity patients.