Cardiac glycosideNARROW THERAPEUTIC INDEXSERUM LEVEL MONITORING
Digoxin
Digoxin BioPhausia · Lanoxin
Na⁺/K⁺-ATPase inhibitor with positive inotropy and vagal AV-node slowing. Rate control fails under adrenergic stress — making it a poor choice for the active patient and a reasonable one for the bedridden.
BOXED WARNING
Toxicity occurs within the therapeutic range in the presence of hypokalaemia, hypomagnesaemia, hypercalcaemia, and renal failure.
Dosing in adults
By indicationuppdaterad 2026-08-19
| Indication | Regimen | Comment |
|---|---|---|
| Rate control, rapid digitalisation | 0,25–0,5 mg iv, repeated to a maximum of 1,5 mg/day | effect after 30–60 min |
| Maintenance | 0,0625–0,25 mg orally daily | guided by weight, age, and eGFR |
| Heart failure with sinus rhythm | 0,125 mg orally daily | target concentration 0,5–0,9 nmol/l |
| Elderly or eGFR < 45 | 0,0625–0,125 mg orally daily | start low, increase slowly |
Renal impairment
Eliminated renally. Halve the dose at eGFR 30–50; avoid or dose by serum level below 30.
Hepatic impairment
No adjustment.
Children
Digitalisation and maintenance by body weight and age — specialist cardiology prescription.
Pitfall
Halve the dose when amiodarone is initiated. In digoxin-induced arrhythmia with hyperkalaemia, give digoxin antibody fragments — not calcium, which can worsen the picture.
Pharmacokinetics
- BIOAVAIL.
- 60–80 % tablet
- Vd
- 5–7 l/kg
- t½
- 36–48 h (longer in renal failure)
- PROTEIN BINDING
- 25 %
- METABOLISM
- Minimal
- EXCRETION
- Renal, unchanged
- SUBSTRATE
- P-glycoprotein
- ONSET
- 1–2 h oral · 30 min iv
Adverse effects by frequency
≥ 10 %
Nausea, loss of appetite, fatigue
1–10 %
Gynaecomastia, confusion, colour vision disturbance with yellow-green tinge
< 1 %
AV block, ventricular arrhythmia, atrial tachycardia with block