Digoxin is not a first line drug. It is indicated for rate control in atrial fibrillation and symptomatic heart failure even in sinus rhythm; it has no role in the prophylaxis of paroxysmal atrial fibrillation.
Seek specialist advice before initiating digoxin in heart failure
For urgent rate control in atrial fibrillation, a loading dose of digoxin may be given intravenously or orally. Intravenous digoxin is potentially hazardous and should be reserved for patients with a clear need for urgent digitalisation
Digoxin may be a useful adjunct to a beta-blocker for heart rate control but assessment of heart rate/rhythm is required and doses more than 125 micrograms in this setting are generally best avoided.
Regular measurements of plasma digoxin concentrations are not usually required except to confirm toxic levels, or to check compliance. Blood should be taken 6 hours or more after the last dose of digoxin. Laboratories in NI offer a normal range. Refer to the UKMI Drug monitoring guidance for further information.
There is no therapeutic dose response relationship for digoxin in heart failure. Increasing doses >250 micrograms just increases toxicity.
If toxicity occurs, digoxin should be withdrawn; serious manifestations require urgent specialist management. For further information on the management of toxicity see Toxbase or contact UK National Poisons Information Service on 0844 892 0111.
Digoxin should not be used in the treatment of patients with pre-excitation syndromes, e.g. Wolff-Parkinson-White Syndrome, unless specifically prescribed by a specialist.
Cautions
Loading and maintenance doses of digoxin should be adjusted according to renal function. Age, sex and weight need to be considered. A maintenance dose of ≤125 micrograms daily is adequate in most patients. A lower maintenance dose (i.e. 62.5 micrograms daily) is often adequate in older patients, in patients with renal failure and in patients taking potentiating therapy-see NHS improvement for further information.
Digoxin should be used with particular caution in the elderly and patients with renal impairment
Hypokalaemia predisposes to digoxin toxicity. Care should be taken to monitor the electrolytes when prescribing diuretics. Consider use of appropriate potassium-sparing diuretics, or combination with ACE inhibitor/ARB as appropriate.
