Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Digoxin

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USE IF: AF rate control (especially sedentary / HF context), HFrEF symptom adjunct β€” with renal dosing, electrolyte surveillance, interaction screen, and toxicity vigilance (GI / vision / rhythm).

AVOID IF: Uncorrected hypokalemia/hypomagnesemia/hypercalcemia with continued dosing; rapid IV push; interaction stacking without level/plan; VF (acute); ignoring renal accumulation.

Digoxin

Cardiac glycoside (inotropic / AV-nodal)

AdultPediatricCardiologyHFAFERWardICU

Indication

AF rate control (rest-biased) β€’ HFrEF symptom adjunct β€’ Selected atrial arrhythmias (specialist)

At a glance

INDICATIONS (CORE USE)

- Atrial fibrillation (rate control, especially sedentary / HF patients) - HFrEF (symptom control; no mortality benefit)

ADULT DOSE (STANDARD)

Maintenance: ~0.125–0.25 mg daily PO (lower in elderly / CKD / low body weight) Loading (if used): IV or PO in divided doses β€” protocol-based only

MAX DOSE

No safe universal β€œmax” β€” individualize to renal function, age, weight, rhythm goal, and toxicity margins

Route

PO / IV

PEDIATRIC DOSE

Specialist / weight-based only

Do not miss

Must-not-miss safety points

Major warning

- Narrow therapeutic index β†’ small dose changes can cause toxicity - Toxicity risk ↑ with renal impairment - Hypokalemia ↑ digoxin toxicity (major trap) - Arrhythmias (bradycardia, AV block, ventricular arrhythmias) - Toxicity can present with GI + visual + cardiac symptoms - Drug interactions are common and clinically significant

Indications

Primary

  • Atrial fibrillation (rate control, especially sedentary / HF patients)
  • HFrEF (symptom control; no mortality benefit)

Secondary

  • Selected atrial arrhythmias (specialist context)

Dosing

STANDARD (ADULT PO)

Maintenance: ~0.125–0.25 mg PO daily (often lower in elderly / CKD) Loading (if used): IV or PO in divided doses β€” protocol-based

ADULT DOSE

Titrate to: - renal function - age - body size Lower doses in elderly, CKD, low body weight Avoid rapid IV bolus (arrhythmia risk)

PEDIATRIC DOSE

Specialist / weight-based only

MAX DOSE

Individualized ceiling β€” avoid fixed β€œmax” labels; reassess with levels/clinical context when available

Practical Note

- Narrow therapeutic index β€” smallest practical dose change - Renal impairment β†’ accumulation β†’ lower maintenance and closer monitoring - Hypokalemia / hypomagnesemia / hypercalcemia β†’ ↑ toxicity β€” correct electrolytes before blaming β€œnon-response” - Loading is not routine outpatient care β€” protocol/specialist decision

Warnings

Clinical warnings

  • AV block / sick sinus syndrome without reliable pacing β€” high bradycardia risk; specialist context
  • Narrow therapeutic window
  • Renal impairment β†’ accumulation
  • Electrolyte imbalance (↓K, ↓Mg, ↑Ca) β†’ ↑ toxicity
  • Bradycardia / high-grade AV block
  • Visual disturbances (yellow/green vision, halos)
  • GI symptoms (nausea, vomiting) β€” often early toxicity

Contraindications

  • Ventricular fibrillation
  • Known hypersensitivity

Drug interactions

  • Loop / thiazide diuretics β†’ hypokalemia β†’ ↑ digoxin toxicity (high-frequency clinical trap)
  • Amiodarone β†’ ↑ digoxin levels / AV nodal effects
  • Verapamil / diltiazem β†’ ↑ levels + AV block / bradycardia risk
  • Macrolides (e.g., clarithromycin) β†’ ↑ levels (CYP / gut flora / P-gp context)
  • P-gp inhibitors (e.g., dronedarone, cyclosporine, selected agents) β†’ ↑ digoxin levels

Special populations

Pediatrics

Specialist / weight-based only

Pregnancy

Pregnancy: use only with clear maternal benefit; follow high-risk cardiology / obstetric protocols.

Lactation

excreted in milk; infant monitoring context β€” verify local guidance.

Renal impairment

Dose reduction required; monitor closely β€” dominant clearance pathway.

Hepatic impairment

Not first-line hepatic adjustment drug; severe liver disease may alter context β€” follow specialist if co-pathology.

Elderly

Elderly: high toxicity risk β€” use lower maintenance doses; tighten monitoring after any change. HFrEF: symptom control adjunct only β€” not a mortality benefit; toxicity margins drive dose decisions.

Administration

- PO daily dosing (consistent timing) - IV: slow administration per protocol β€” avoid rapid IV push (arrhythmia risk)

Monitoring

  • Monitor: - HR / rhythm - Symptoms (GI, visual, cardiac) - Renal function - Electrolytes (K, Mg); Ca when relevant
  • Recheck: - After any dose change - If toxicity suspected - Periodically on chronic therapy - Reassess early when diuretics, amiodarone, macrolides, or P-gp inhibitors are started/stopped
  • Hold if:
    - Bradycardia / symptomatic bradycardia
    - AV block (per clinical severity and pacing availability)
    - Suspected toxicity

Overdose / toxicity

Clinical Picture

GI: nausea, vomiting CNS: confusion, visual changes Cardiac: bradycardia, AV block, ventricular arrhythmias

Immediate Actions

Stop digoxin Check K, Mg, renal function ECG monitoring Correct precipitating electrolytes when safe

Antidote

Digoxin-specific antibody fragments (Digoxin immune Fab)

Decontamination

Acute oral overdose: supportive care; toxicology for Fab dosing and refractory arrhythmias.

Escalation

ICU for severe arrhythmias, hemodynamic instability, or Fab-refractory course per protocol.

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield

  • Always think K⁺ (and Mg²⁺) when using digoxin
  • Most toxicity = dosing + renal function + electrolytes + interactions

Clinical

  • In AF, often better for resting rate control than exertional rate

Safety

  • Check drug interactions before prescribing or adding new therapy

Pharmacy Tool

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Digoxin 0.05 mg/mL oral solution

solution Β· oral

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Pharmacokinetics

- Renal clearance dominant - Long half-life - Narrow therapeutic index

Mechanism of action

- Na⁺/K⁺ ATPase inhibition β†’ ↑ intracellular Ca²⁺ β†’ ↑ contractility + ↑ vagal tone β†’ slowed AV conduction

Common brand names

Saudi Arabia

Lanoxin, Digoxin

Global

Digitek, (placeholder β€” verify local formulation)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

Global data (no country-specific data available)

  • Follow local antimicrobial stewardship policy, hospital formulary, and national resistance guidance.
  • Confirm dosing, stock, and restrictions with institutional pharmacy and current product labeling.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • ACC / AHA / HRS atrial fibrillation management references (where applicable)
  • ACC / AHA heart failure guideline digoxin positioning (where applicable)
  • Extracellular Cardiac Glycoside Toxicity references / ACLS adjuncts (institutional)
  • FDA / SFDA product labeling