Digoxin

Lanoxin, Digox, Digitek

Cardiac glycoside • Cardiac glycoside

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NTIQT Risk

Half-life

36-48 hours

Protein Binding

20-30%

Metabolized By

N/A

External

Drugs.com

Clinical alerts

Narrow therapeutic index

Small dose changes can cause toxicity or loss of effect

QT prolongation

Avoid combining with other QT-prolonging agents; check electrolytes

Mechanism of action

Inhibits Na+/K+-ATPase, increasing intracellular calcium and cardiac contractility

Recorded indications

From the drug index — may include conditions studied rather than approved indications

·Atrial fibrillation — ventricular rate control
·Atrial flutter
·Heart failure with reduced ejection fraction (HFrEF)

Dosing

Typical adult starting point — always confirm against local guidelines

Typical dose: [object Object] mg every 24 h; Oral
Loading dose: [object Object] mg

Monitoring

Therapeutic range: 0.8–2 ng/mL; Trough
Steady state: ~7 days
Re-check: Weekly initially; then every 6 months

At least 6 hours post-dose (distribution phase)

Interactions

4 curated · 3 major or contraindicated · select a row for management

Interacting drug	Severity	Effect
amiodarone	major	Digoxin toxicity with cardiac arrhythmias.
clarithromycin	major	Significantly elevated digoxin levels and toxicity risk
verapamil	major	50-75% increase in digoxin levels plus bradycardia/AV block risk
rifampicin	moderate	Reduced digoxin levels; risk of loss of rate/rhythm control.

Common adverse effects

Nausea
Visual disturbances
Arrhythmias
Anorexia

Food, alcohol & herbal

Food

High-fiber meals may decrease absorption

Alcohol · minor

Minimal direct interaction

Herbal

St. John's Wort (major) — Reduces digoxin levels via P-gp induction
Licorice (major) — May cause hypokalemia, increasing digoxin toxicity

Pharmacokinetics

Published parameters · PMID:2871386

Half-life: 36-48 hours
Protein binding: 20-30%
Clearance: 7 L/h; adult heart failure patients
Volume of distribution: 500 L
Bioavailability: 70%
Renally eliminated: 70%; Dose review in renal impairment
Model: 2-compartment

Pregnancy & lactation

Pregnancy category: C
Lactation: safe

Sources

Assembled from: drug index, curated drug database, curated interaction pairs, published PK literature, TDM population profiles.

Not a substitute for clinical judgement