Theophylline toxicity
See theophylline for general drug information.
Background
- Primarily used as a bronchodilator, however rarely used now due to better available options
- Also studied for treatment of Acute Mountain Sickness and Contrast-Induced Nephropathy
- PO available as elixer and capsule (12 or 24-hour extended release)
- IV as aminophylline (shorter acting than PO)
- Mechanism of action[1]:
- Release of endogenous catecholamines → β2 agonism → bronchodilation
- PDE inhibition → increases cAMP
- Adenosine antagonist
Clinical Features
- Cardiovascular
- Sinus Tachycardia
- Atrial/Ventricular arrhythmias
- Hypotension (due to β2-mediated vasodilation)
- Metabolic
- Neurologic
- Tremor
- Agitation
- Seizure
- GI
Differential Diagnosis
Evaluation
- Theophylline level
- ECG
- Metabolic panel
- Lactic acid level
- CK
Management
- Supportive care is the mainstay of treatment
- Cardiovascular
- Consider norepinephrine (alpha-agonist) for hypotension
- Refractory hypotension may respond to non-selective beta-blockers[1]
- GI decontamination (Multidose Activated Charcoal, Whole Bowel Irrigation)
- Consider in recent severe overdose
- Contraindications: unsecured airway, nausea/vomiting, ileus, Bowel Obstruction, or need for emergent endoscopy
- Seizures
- 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