Digoxin Loading Dose Guide (Adults) - NHS Dorset

[Pages:2]Digoxin ? Loading Dose Guide (Adults)

? Digoxin is indicated for rate control treatment of atrial fibrillation ? occasionally for the use in heart failure

? in the management of certain supraventricular arrhythmias, particularly atrial fibrillation and flutter, where its major beneficial effect is to reduce the ventricular rate.

Check the drug history

Digoxin-induced cardiac toxicity may resemble the presenting cardiac abnormality. If toxicity is suspected, a plasma level is required prior to giving additional digoxin.

When to use

The intravenous route should be reserved for use in patients requiring urgent

IV loading

digitalisation, or in patients who are nil by mouth.

All IV doses require ECG monitoring

INTRAVENOUS DIGOXIN

? A large peripheral vein should be used for administration. Patients having peripheral

administration must be observed closely for signs of phlebitis

? If a patient has a central venous catheter this should be used for administration due to high osmolality.

IV loading

500mcg-1000mcg given in divided doses by intravenous infusion (Usual practice is to give

dose

500mcg followed by 500mcg 6 hours later).

Dilute up to 500mcg (2ml) of digoxin with 50-100ml of sodium chloride 0.9% or glucose 5% (maximum concentration 62.5mcg/ml) and give by intravenous infusion over at least 2 hours

(faster infusion rates can be used in appropriate high care environments)

Or In urgent cases: Dilute 500mcg (2ml) of digoxin with at least 8ml of sodium chloride 0.9% or glucose 5% (total volume = 10ml) and give by slow intravenous injection over 10-20 minutes

The age, serum potassium levels and renal function of the patient should also be taken into account when dosing digoxin.

Loading doses are not needed for treatment of heart failure in sinus rhythm.

Oral loading dose

Oral Maintenance dose Bioavailability

1.5mg in divided doses over 24 hours.(Usual practice is to give 500mcg followed by 500mcg 6 hours later). The loading doses may need to be reduced: if digoxin or another cardiac glycoside has been given in the preceding two weeks, in the elderly and in those with impaired renal function After loading dose clinically assess patient and prescribe maintenance dose if indicated.

Revert to oral therapy as soon as possible. Usual range is: Atrial fibrillation or flutter: 125mcg to 250mcg every morning Heart failure for patients in sinus rhythm: 62.5mcg to 125 micrograms every morning Reduce dose is required in renal impairment and when co-prescribed amiodarone

125 microgram tablet is bioequivalent to 100 microgram elixir ( 50 micrograms/mL) and to 100 microgram injection

Ideal sampling time

At least 6 hours post IV dose At least 6 hours post or pre oral dose

Reasons to check level Routine levels are NOT recommended

Renal impairment, lack of response, interacting medication started or stopped, symptoms of toxicity

Therapeutic drug monitoring

Accepted therapeutic range = 0.9 to 2.0 micrograms per litre

Toxic effects

Nausea, vomiting, diarrhoea, visual disturbances, arrhythmias ? typically ventricular extrasystoles and atrial tachycardia with varying AV block, sinus bradycardia

Monitoring

Major factors influencing serum levels

Monitor ECG, heart rate and blood pressure Cardiac side-effects of digoxin are enhanced by acidosis, hypokalaemia, hypomagnesaemia, hypercalcaemia, hypoxia and hypothyroidism

Renal impairment, congestive heart failure, hyperthyroidism, hypothyroidism. Interacting medicines e.g. amiodarone, amphotericin, ciclosporin, dronedarone, diltiazem, diuretics, hydroxychloroquine, lercanidipine, nicardipine, nifedipine, verapamil, quinine, St John's wort. This is not an exhaustive list. Refer to the BNF for full list

Faye Thornton, Pharmacy, Vivek Kodoth, Cardiology Consultant February 2021

1

Adapted with permission from a guideline by Dorset County Hospital NHS Trust (Author Christine Dodd, Clinical Pharmacy Manager).

Review Date: February 2024

Digoxin Loading Dose

Oral Loading Dose

IV Loading Dose

Stat dose 500 mcg PO*

6 hours later 500 mcg PO*

Check Digoxin Level

48 hours after initiation of maintenance doses

500 to 1000 mcg total dose*

Stat dose 500 mcg IV*

6 hours later 500 mcg IV*

*Consider adjusting dose in:

Renal Impairment Elderly

Recent cardiac glycosides

Faye Thornton, Pharmacy, Vivek Kodoth, Cardiology Consultant February 2021

2

Adapted with permission from a guideline by Dorset County Hospital NHS Trust (Author Christine Dodd, Clinical Pharmacy Manager).

Review Date: February 2024

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