Certain cardiac conditions, such as intermittent complete heart block, myocarditis, second degree atrioventricular block, supraventricular arrhythmias associated with accessory conducting pathways, and ventricular tachycardia or fibrillation, are contraindications to prescribing digoxin. Digoxin should be used with caution in some patients, such as those with renal impairment.
Patients on digoxin require periodic monitoring of their renal function and adjustment of their digoxin dose if creatinine clearance has changed.
Routine monitoring of serum digoxin concentration is not recommended. Measure serum digoxin concentration 2-3 weeks after any change in therapy or addition of a new medication. Serum digoxin concentrations are unreliable if obtained earlier than 6 hours after a dose of digoxin.[20]Gheorghiade M, van Veldhuisen DJ, Colucci WS. Contemporary use of digoxin in the management of cardiovascular disorders. Circulation. 2006 May 30;113(21):2556-64.
http://www.ncbi.nlm.nih.gov/pubmed/16735690?tool=bestpractice.com
Note that toxicity can occur even when the serum digoxin concentration is within the therapeutic range, though this is extremely rare. Interpret results within the clinical context.[21]National Institute for Health and Care Excellence. Chronic heart failure in adults: diagnosis and management. September 2018 [internet publication].
https://www.nice.org.uk/guidance/ng106
Patients with renal impairment, hypokalaemia, hypomagnesaemia, and hypothyroidism may be at higher risk of digoxin intoxication than others.[20]Gheorghiade M, van Veldhuisen DJ, Colucci WS. Contemporary use of digoxin in the management of cardiovascular disorders. Circulation. 2006 May 30;113(21):2556-64.
http://www.ncbi.nlm.nih.gov/pubmed/16735690?tool=bestpractice.com
Alternative treatments are effective for two of the major clinical indications for digoxin, congestive heart failure and atrial fibrillation, and may be considered in place of digoxin, particularly in a patient who has experienced toxicity.[20]Gheorghiade M, van Veldhuisen DJ, Colucci WS. Contemporary use of digoxin in the management of cardiovascular disorders. Circulation. 2006 May 30;113(21):2556-64.
http://www.ncbi.nlm.nih.gov/pubmed/16735690?tool=bestpractice.com
[36]Rathore SS, Curtis JP, Wang Y, et al. Association of serum digoxin concentration and outcomes in patients with heart failure. JAMA. 2003 Feb 19;289(7):871-8.
http://www.ncbi.nlm.nih.gov/pubmed/12588271?tool=bestpractice.com