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Digoxin (Lanoxin)

Antiarrhythmic / Inotropeprescriptionoral · inferred

Cardiac glycoside that inhibits sodium-potassium ATPase, increasing intracellular sodium and calcium via the sodium-calcium exchanger, producing positive inotropy. Also enhances vagal tone, slowing AV conduction. Narrow therapeutic index (0.5-2.0 ng/mL) with toxicity risk increased by hypokalemia, hypomagnesemia, and hypercalcemia. P-glycoprotein substrate — amiodarone, verapamil, macrolides, and quinidine can double or triple digoxin levels, often requiring 30-50% dose reduction.

Projected serum levels — 0.13 mg, once daily

Digoxin (Lanoxin)
Digoxin (Lanoxin) modeled serum levels, 0.13 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 5 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 5
Digoxin (Lanoxin) modeled serum levels with a loading dose of 0.36 mg, then 0.13 mg once daily The first dose is larger so levels approach steady state faster. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 0.13 mg once daily (oral).

Loading schedule: 0.36 mg on day 1, then 0.13 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~5 days: peak ≈ 0.24 mg, trough ≈ 0.17 mg body load. Population-based estimate over 15 days for a 0.13 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antiarrhythmic / Inotrope
Route modeled
Oral
Model confidence
inferred
Half-life
40 h
Common dose
0.13 mg
Suggested maximum
0.50 mg/day
Reference dose range
0.063–0.50 mg (single dose)
Suggested cadence
once daily
Validated against
0.25 mg oral — Cmax 0.001 mg/L at 2 h

Documented interactions

  • contraindicated
    Carbamazepine (Tegretol) + Digoxin (Lanoxin) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~0.20x

  • contraindicated
    Clarithromycin (Biaxin) + Digoxin (Lanoxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~10.00x

  • contraindicated
    Dasatinib (Sprycel) + Digoxin (Lanoxin) CYP inhibition

    Dasatinib (Sprycel) time_dependent_inhibitor of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~5.00x

  • contraindicated
    Diltiazem + Digoxin (Lanoxin) CYP inhibition

    Diltiazem mechanism_based of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~10.00x

  • contraindicated
    Efavirenz (Sustiva) + Digoxin (Lanoxin) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~0.12x

  • contraindicated
    Grapefruit (whole fruit) + Digoxin (Lanoxin) CYP inhibition

    Grapefruit (whole fruit) mechanism_based of CYP3A4 predicted to change Digoxin (Lanoxin) AUC by ~10.00x

Serum checks 77 modeled interaction pairings for digoxin (lanoxin) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. The Effect of Digoxin on Mortality and Morbidity in Patients with Heart Failure The Digitalis Investigation Group · New England Journal of Medicine, 1997 DOI

    Landmark DIG trial (n=6,800) showing digoxin reduces heart failure hospitalizations by 28% but has a neutral effect on all-cause mortality in systolic HF. Established digoxin's role in reducing morbidity but not…

  2. Withdrawal of digoxin from patients with chronic heart failure treated with angiotensin-converting-enzyme inhibitors Packer M et al. (RADIANCE Investigators) · New England Journal of Medicine, 1993 DOI

    Landmark RADIANCE trial demonstrating that withdrawing digoxin from stable HF patients on ACE inhibitors leads to clinical deterioration — worsening HF, reduced exercise tolerance, and lower ejection fraction. Confirmed…

2 published studies referenced in the app, each with a plain-language summary.