A. Causes [2]
- Most commonly due to elevated levels of digoxin in serum
- Drug overdose
- Drug interactions
- Precipitated by hypokalemia
- Progressive renal failure
- Ingestion of Digitalis or Related Cardiac Glycosides
- Foxglove plant (Digitalis purpurea)
- Wooly foxglove (Digitalis lanata)
- Ornamental oleander (Nerium oleander)
- Yellow oleander (Thevetia peruviana)
- Squill or sea onion (Uriginea maritima)
- Lily of the valley (Convallaria majalis)
- Ouabain (Strophanthus gratus)
- Determine serum digitoxin levels (rather than digoxin)
- Cardiac glycosides from skin of certain toads (found in some herbal remedies)
B. Symptoms
- Anorexia, Nausea, Vomiting, Diarrhea
- Blurred vision
- Color distortion
- Yellow halo around lights
- Photophobia
- Cardiac Conduction Anomalies
- Cardiac glycosides increase vasal (parasympathetic) activity
- Atrioventricular block
- Slow sinus rate (sinus bradycardia)
- Extrasystole (atrial and ventricular)
- Usually responds transiently to atropine
- Malignant Arrhythmias
C. Drug Interactions Affecting Digoxin Levels [3]
- Increases Digoxin Levels
- Quinidine
- Amiodarone
- Erythromycin
- Propafenone
- Verapamil
- Spironolactone
- Decreases Digoxin Levels
- Sulfasalazine
- Cholestyramine
- Antacids
D. Treatment
- Supportive care
- Stop digoxin
- Reduce Absorption
- Charcoal may be useful since digoxin undergoes significant enterohepatic recirculation
- Cholestyramine
- Maintain Serum K+ >4.5mEq (hypokalemia can precipitate severe arrhythmias)
- Normalize serum Na+, Mg2+
- Phenytoin (dilantin) or lidocaine may be used to treat arrhythmias
- Dixogin specific Fab fragments (see below)
- Dialysis is generally not helpful due to high volume of distribution
E. Indications for Anti-Digoxin Fab' Fragments (Digibind®) [4,5]
- Shock or Cardiac Arrest or Ventricular Tachycardia
- AV Block or Sinus Bradycardia unresponsive to atropine
- Digoxin Level >10ng/mL or ingestion of >10mg digoxin
- Hyperkalemia with any other signs of digoxin toxicity
- Impaired clearance of drug in renal failure - lower threshold for use of Fab'
- May also be effective for treatment of ingestion of yellow oleander [6]
References
- Brunner G, Zweiker R, Krejs GJ. 2000. Lancet. 356(9239):1406 (Case Report)

- Newman LS, Feinberg MW, LeWine HE. 2004. NEJM. 351(6):594 (Case Discussion)

- Krisanda TJ. 1992. Postgrad Med. 91(6):273

- Ujhelyi MR, Robert S, Cummings DM, et al. 1993. Ann Intern Med. 119(4):273

- Digibind. 1986. Med Let. 28(722):87
- Eddleston M, Rajapakse S, Jayaleth RS, et al. 2000. Lancet. 355(9208):967
