In low to moderate doses, methylxanthines cause mild cortical arousal and insomnia, much like caffeine.  Acute theophylline intoxication results in nausea/vomiting, abdominal pain, diarrhea, cardiac arrhythmias, and seizures.  Seizures are the major cause of morbidity and mortality in theophylline intoxication.  Tachyarrhythmias are the other major concern but usually do not cause QT prolongation.

Treatment of theophylline intoxication includes administration of activated charcoal to reduce gastrointestinal absorption.  Beta blockers are the drugs of choice for theophylline-induced cardiac tachyarrhythmias.  Theophylline-induced seizures are difficult to treat, but benzodiazepines and barbiturates are the most effective agents.

(Choice A)  Iron poisoning can cause hematemesis and melena as iron is directly toxic to gastric mucosal cells.

(Choice B)  Bradycardia, hypotension, and hypoglycemia are seen with beta blocker toxicity.  Glucagon is the specific antidote as it increases intracellular cyclic adenosine monophosphate and cardiac contractility.

(Choice C)  Acetaminophen causes liver damage following a latent period.  Acetylcysteine, a glutathione donor, is used to treat acetaminophen toxicity.

(Choice D)  Severe sedation, respiratory depression, and constricted pupils are features of opioid intoxication.  Treatment includes general supportive care and administration of opioid antagonists such as naloxone.

Educational objective:
Seizures are the major cause of morbidity and mortality from theophylline intoxication.  Tachyarrhythmias are the other major concern.