Drug interactions
Digoxin + Theophylline
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Overview
Additive arrhythmogenic potential; theophylline can cause tachyarrhythmias and hypokalemia, which increases susceptibility to digoxin toxicity.
Mechanism of action
Pharmacodynamic: Theophylline’s catecholaminergic effects and potential to lower K+/Mg2+ enhance digoxin-related arrhythmias; no consistent pharmacokinetic interaction.
Clinical management
Monitor heart rate/ECG and serum K+/Mg2+, particularly during initiation, dose changes, or intercurrent illness; maintain K+ >4 mEq/L and Mg2+ >2 mg/dL; consider checking digoxin levels if symptoms of toxicity or electrolyte disturbances occur.
Drug reference
References
- Theophylline: Pharmacology, administration, and adverse effects — UpToDate
- Digoxin toxicity — UpToDate
- Theophylline: Drug Interactions — Lexicomp
Frequently asked questions
Can I take Digoxin with Theophylline?
The interaction is rated: Moderate. Additive arrhythmogenic potential; theophylline can cause tachyarrhythmias and hypokalemia, which increases susceptibility to digoxin toxicity.
How serious is the interaction between Digoxin and Theophylline?
The interaction is rated: Moderate. Evidence level: Low.
How is the interaction between Digoxin and Theophylline managed?
Monitor heart rate/ECG and serum K+/Mg2+, particularly during initiation, dose changes, or intercurrent illness; maintain K+ >4 mEq/L and Mg2+ >2 mg/dL; consider checking digoxin levels if symptoms of toxicity or electrolyte disturbances occur.
Why do Digoxin and Theophylline interact?
Pharmacodynamic: Theophylline’s catecholaminergic effects and potential to lower K+/Mg2+ enhance digoxin-related arrhythmias; no consistent pharmacokinetic interaction.
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