Theophylline Toxicity Clinical Presentation

Updated: Nov 29, 2023
  • Author: Christopher P Holstege, MD; Chief Editor: Stephen L Thornton, MD  more...
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Signs and symptoms of theophylline toxicity correlate better with single acute ingestions than with chronic overexposures. Clinical manifestations of acute theophylline overdose are as follows:

  • Nausea
  • Vomiting
  • Abdominal pain
  • Tachycardia

In addtion, patients may manifest features of the following:

  • Metabolic acidosis
  • Hypokalemia
  • Hypophosphatemia
  • Hypocalcemia/hypercalcemia
  • Hyperglycemia

Chronic theophylline overdose has minimal gastrointestinal clinical effects. Seizures, hypotension, and significant dysrhythmias usually are observed when serum levels approach 80 mcg/mL. Seizures were more commonly reported with acute overdose than with chronic overdose. In long-term exposures, seizures may develop at lower serum concentrations (40-60 mcg/mL). Cardiac dysrhythmias are more common following a chronic overdose with lower serum concentrations.


Physical Examination

Cardiovascular findings include the following:

Pulmonary findings include increased respiratory rate leading to respiratory alkalosis, acute lung injury (ALI), and respiratory failure. Neurological signs include tremors (most common), restlessness, agitation, and altered mental status. Persistent seizures may occur with serum levels > 25 mcg/mL. Gastrointestinal manifestions are nausea, vomiting, abdominal cramps, and diarrhea.