For atrial fibrillation and heart failure · Written by the Lyng Pharmacy team, based on NHS and BNF guidance · Updated August 2026
Also sold asLanoxin
Type of medicineCardiac glycoside
Available asTablets, oral solution, injection
How you get itPrescription only
Digoxin slows and strengthens the heartbeat. It has been in use for over two centuries and remains useful in atrial fibrillation and heart failure, but it has a narrow safety margin — the difference between a working dose and a toxic one is small.
How to take it
Once daily, at the same time each day, with or without food.
Do not stop or change the dose without medical advice.
Blood tests check kidney function and potassium, and sometimes the digoxin level itself. Levels are taken at least six hours after a dose — keep to your usual dosing time before a test.
Toxicity — the signs
Contact your doctor promptly for: nausea, vomiting or loss of appetite; diarrhoea; confusion or unusual drowsiness; visual changes, particularly blurred or yellow-green tinged vision or halos around lights; or a very slow, fast or irregular pulse. These can indicate digoxin toxicity.
Toxicity is often triggered by something other than the dose:
Low potassium or magnesium — often caused by diuretics
Worsening kidney function, including from dehydration
Interacting medicines: amiodarone, verapamil, diltiazem, clarithromycin, some antifungals, and St John’s wort
If you are prescribed a diuretic alongside digoxin, the potassium checks matter — do not skip them.
Everyday points
Tell any prescriber that you take digoxin before starting anything new, including over-the-counter and herbal products.
Report significant vomiting or diarrhoea, which can dehydrate you and raise digoxin levels.
If you miss a dose, take it if you remember within about 12 hours; otherwise skip it. Never double up.
Always read the label. This page is general information, not advice for your situation. Doses, warnings and interactions differ between products and between people. Check the leaflet inside your medicine, and ask our pharmacist if anything is unclear — that conversation is free and takes two minutes.
Questions about Digoxin?
1 Lyng Lane, West Bromwich B70 7RW · Mon–Fri 8:30am–6pm, Sat 9am–1pm · 0121 500 5756
Nausea, vomiting, loss of appetite, diarrhoea, confusion, visual changes such as yellow-green tinged vision or halos, and a very slow or irregular pulse. Contact your doctor promptly.
Why does potassium matter on digoxin?
Low potassium, often caused by diuretics, makes digoxin toxicity far more likely. That is why the blood tests are important.
Which medicines interact with digoxin?
Amiodarone, verapamil, diltiazem, clarithromycin, some antifungals and St John’s wort among others. Always tell prescribers you take digoxin.
Can dehydration affect digoxin?
Yes. Vomiting, diarrhoea or dehydration can reduce kidney function and raise digoxin levels. Report significant illness.
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