Theophylline Overdose
                        =====================

þ Symptoms of Theo Toxicity
 - nausea, vomiting, and abdominal pain, and CNS stimulation
   including agitation, tremor, seizures, and rarely coma.
 - May cause cardiac irritability and arrhythmias.
 - The occurrence of seizures does not appear to correlate with
   the prognosis in a patient with theophylline toxicity.
   Ref: Tintinalli 3rd ed. p 614

þ Acute vs. Chronic Theo Toxicity
 - as chronic toxicity is worse for the same serum level (higher pre-existing
   tissue levels from chronic use).
 - Hypokalemia, low serum bicarbonate, and hypotension suggest acute
   overdose.  [Am J Emerg Med 1985;3:386-394.]
 - Seizure levels (approx):
  + Acute ingestion:    60-100 mcg/ml, often delayed
  + chronic toxicity:   20-60 mcg/ml
 - Fatal levels (approx)
  + acute ingesions:    100 mcg/ml.
  + chronic toxicity:   40-60 mcg/ml.

þ Treatment:  Decontamination and GI dialysis
 - Sustained-release preparations mean that gastric decontamination very
   important.
 - Due to enterohepatic recirculation of theophylline, GI dialysis (multiple
   dose oral activated charcoal) can be effective in managing; just as good as
   charcoal hemoperfusion if patient can take PO charcoal, and with less risk
   of complications.
   [N Engl J Med 1979;300:24-26.]
   [Am Rev Respir Dis.1983;128:820-822.]
 - May give as constant NG infusion and use without sorbitol to avoid vomiting.
   [Ped Pharmacol. 1986;5:241-245.]
   [Ann Emeg Med. 1990;19:453.]
 - Vomiting: Ranitidine and droperidol may help prevent vomiting.
   Avoid cimetidine as may interfere with theophylline metabolism.
   [Ann Intern Med 1986;105:386-387.]

þ Charcoal Hemoperfusion
 - With severe toxicity and vomiting, charcoal hemoperfusion can be effective.
 - Guidelines for using:  as levels approach 80-100 mcg/ml, or develop signs of
   significant toxicity, should consider charcoal hemoperfusion.