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Expected pharmacological effect
Causality assessment · Expected pharmacological effect
Digoxin and Bradycardia / AV block: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Digoxin ↔ Bradycardia / AV block
n=2,533 co-reports · PRR 14.7 · ROR 15.2
Digoxin inhibits the sodium–potassium ATPase and raises vagal tone, so slowing of atrioventricular conduction is the direct, dose-related extension of its intended pharmacology rather than an idiosyncratic effect. Bradycardia and AV block cluster in older patients, in renal impairment (reduced digoxin clearance), and with electrolyte disturbance or interacting drugs such as amiodarone, verapamil, and beta-blockers. The 2,533 co-reports (PRR 14.7) reflect both a genuine effect and the very large population still taking a centuries-old drug.
Regulatory basis: digoxin prescribing information (bradycardia/AV block; therapeutic drug-level and ECG monitoring).
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Bradycardia appears during exposure and resolves on dose reduction or withdrawal |
| Strength | met | PRR 15 on a large co-report count for a drug whose whole mechanism slows conduction |
| Consistency | met | Reproduced across decades of use and in the prescribing literature |
| Specificity | partial | Shared with other AV-node-slowing drugs (beta-blockers, verapamil, amiodarone) |
| Biological gradient | met | Risk rises with dose, renal impairment, and electrolyte disturbance |
| Plausibility | met | Na/K-ATPase inhibition plus raised vagal tone directly slow the AV node |
| Coherence | met | Coheres with routine therapeutic drug-level monitoring for digoxin |
| Experiment | partial | Dechallenge (dose reduction or withdrawal) reliably reverses it; no dedicated randomized trial |
| Analogy | met | Analogous to bradycardia with other AV-nodal blocking agents |
This page's own qualitative read, not an automated/citation-gated assessment.
✗ No ClinicalTrials.gov results-posting trial in the top search hits for digoxin captured bradycardia or AV block as a tracked adverse event — such a familiar, monitorable effect is handled by routine drug-level and ECG monitoring rather than coded into trial AE tables.