Theophylline toxicity

See theophylline for general drug information.

Background

• Still used in patients with debilitating brochospastic disease
• Studied for treatment of Acute Mountain Sickness and Contrast-Induced Nephropathy
• PO in elixir, extended release, or controlled release forms but absorption erratic
• IV as aminophylline
• Adenosine antagonism, Increase catecholamines, and Phosphodiesterase inhibition

Clinical Features

• Neurologic
  • Tremor
  • Agitation
  • Seizure
• Cardiovascular
  • Sinus Tachycardia
  • Atrial/Ventricular arrhythmias
  • Hypotension
• Metabolic
  • Hypokalemia
  • Metabolic Acidosis
  • Hyperthermia
  • Rhabdomyolysis
  • Hyperglycemia
• GI
  • Nausea/Vomiting

Differential Diagnosis

• Beta-2 agonist toxicity
• Sympathomimetic toxicity
• Iron toxicity
• Salicylate toxicity

Evaluation

• ECG
• Chem
• CK
• Theophylline level

Management

1. Supportive care
   • Cardiac monitoring
   • Ondansetron (Zofran) for antiemetic
   • EEG for sedated and paralyzed patients
2. Cardiovascular
   • IV Fluids for hypotension
   • Beta blockers for tachyarrhymias
     • Controversial, involve a toxicologist
3. GI decontamination (Multidose Activated Charcoal, Whole Bowel Irrigation)
   • Considered in life-threatening overdose
     • contraindications: unsecured airway, nausea, vomiting, ileus, Bowel Obstruction, or need for emergent endoscopy
4. Seizures
   • Lorazepam (Ativan) 1st line
   • Phenobarbital if lorazepam ineffective
   • Phenytoin (Dilantin) contraindicated as increases seizure in animal studies
5. Dialysis
   • Indicated in seizures, severe arrhythmias
   • Theophylline level >90mcg/ml in acute ingestion
   • Theophylline level >40mcg/ml in chronic ingestion

Disposition

Immediate release

• Home after 6 hours if:
  • nontoxic
  • asymptomatic
  • and, normal vital sign

Sustained release

• Home after 12 hours if:
  • nontoxic
  • asymptomatic
  • and, normal vital sign

See Also

• Toxicology (main)

References

Authors

Silas Chiu, Ross Donaldson, Neil Young, Daniel Ostermayer, Joe Carpenter