What is the treatment for an aminophylline (aminophylline) overdose?

Aminophylline Overdose Management

Aminophylline overdose requires immediate discontinuation of the drug, aggressive supportive care focused on airway protection and cardiovascular monitoring, and rapid treatment of life-threatening complications including seizures and arrhythmias, with activated charcoal administration and consideration of extracorporeal removal in severe cases. 1

Immediate Actions

Stop aminophylline administration immediately upon recognition of overdose or toxic serum theophylline concentrations >30 mcg/mL 1

• Establish intravenous access, secure the airway, and initiate continuous electrocardiographic monitoring 1
• Contact a regional poison center for updated guidance on individualizing treatment recommendations 1
• The primary hazards include aspiration, hypoventilation, hypoxia, hypotension, and cardiac arrhythmias 2

Clinical Manifestations by Overdose Type

Acute Overdose

• Nausea, vomiting, tachycardia, tremor, agitation, and seizures are the predominant features 1
• Seizures typically occur at serum concentrations >30 mcg/mL and are often resistant to anticonvulsant therapy 1
• Metabolic derangements include hypokalemia, hyperglycemia, and metabolic acidosis 1

Chronic Overdose

• Patients >60 years are at greatest risk for severe toxicity and mortality after chronic overdosage 1
• Severity correlates more strongly with patient age than peak serum concentration 1
• Pre-existing cardiac or neurologic disease significantly increases susceptibility to specific toxic manifestations 1

Seizure Management

Seizures represent the most dangerous complication and require rapid, aggressive treatment due to high associated morbidity and mortality 1

• Initiate intravenous benzodiazepine (diazepam 0.1-0.2 mg/kg every 1-3 minutes) until seizures terminate 1
• For repetitive seizures, administer phenobarbital loading dose (20 mg/kg infused over 30-60 minutes) 1
• Phenytoin is ineffective for theophylline-induced seizures and should not be used 1
• Be prepared for assisted ventilation, as anticonvulsant doses required may cause severe respiratory depression, particularly in elderly patients and those with COPD 1
• Barbiturate-induced coma or general anesthesia may be necessary for status epilepticus 1

Prophylactic Anticonvulsant Therapy

Consider prophylactic treatment in high-risk patients 1:

• Acute overdose with serum concentrations >100 mcg/mL 1
• Chronic overdose in patients >60 years with concentrations >30 mcg/mL 1
• Anticipated delays in extracorporeal removal 1
• Intravenous phenobarbital (20 mg/kg over 60 minutes) may delay or prevent life-threatening seizures 1

Cardiac Arrhythmia Management

• Sinus tachycardia and simple ventricular premature beats do not require treatment in the absence of hemodynamic compromise and resolve with declining serum concentrations 1
• Life-threatening arrhythmias may occur, particularly in patients with underlying cardiac disease 1
• Death from theophylline toxicity most often results from cardiorespiratory arrest and/or hypoxic encephalopathy following prolonged seizures or intractable arrhythmias 1

Enhanced Elimination

Activated Charcoal

• Administer activated charcoal in selected cases to reduce drug absorption 2
• Multiple-dose activated charcoal may enhance elimination in appropriate patients 1

Extracorporeal Removal

• Consider hemodialysis or continuous renal replacement therapy in severe overdose 2
• Particularly indicated in high-risk patients with markedly elevated serum concentrations or refractory symptoms 1

Monitoring Requirements

• Continuous cardiac monitoring throughout treatment 1
• Serial serum theophylline concentrations 1
• Electrolytes, particularly potassium and magnesium 1
• Serum calcium, creatine kinase, myoglobin, and leukocyte count 1
• Blood glucose monitoring 1

Critical Pitfalls to Avoid

• Never use neuromuscular blocking agents alone to terminate seizures, as they only abolish musculoskeletal manifestations without stopping brain seizure activity 1
• Avoid fluorinated volatile anesthetics (particularly halothane) if general anesthesia is required, as they sensitize the myocardium to catecholamines; enflurane is safer 1
• Do not underestimate toxicity risk in elderly patients with chronic overdose, even at lower serum concentrations 1
• Recognize that patients with neurologic disorders have increased seizure risk and cardiac patients have increased arrhythmia risk at any given serum concentration 1

Additional Complications

• Acute myocardial infarction may occur 1
• Urinary retention in men with obstructive uropathy 1
• Irreversible brain injury may result from prolonged uncontrolled seizures 1