Can Digoxin Toxicity Cause Diarrhea?
Yes, diarrhea is a recognized gastrointestinal manifestation of digoxin toxicity, though it occurs less commonly than anorexia, nausea, and vomiting. 1
Gastrointestinal Manifestations of Digoxin Toxicity
The FDA drug label explicitly lists diarrhea among the gastrointestinal adverse effects of digoxin, stating that "digoxin may cause anorexia, nausea, vomiting, and diarrhea." 1 While the European Society of Cardiology emphasizes that anorexia, nausea, and vomiting are the most common gastrointestinal symptoms, diarrhea is still part of the recognized toxicity profile. 2
Relative Frequency of GI Symptoms
Gastrointestinal disturbances historically accounted for approximately one-fourth of all digoxin adverse reactions. 1
In controlled clinical trials, the most common manifestations of digoxin toxicity included gastrointestinal and cardiac disturbances, with CNS manifestations being less common. 1
In a large mortality trial, the incidence of hospitalization for suspected digoxin toxicity was 2% in patients taking digoxin compared to 0.9% in placebo patients. 1
Clinical Context and Diagnostic Approach
Diarrhea should be considered as part of the constellation of symptoms when evaluating for digoxin toxicity, but it is not typically the presenting or most prominent gastrointestinal symptom. 2, 1 The American College of Cardiology recommends that diagnosis be established by the combination of:
- Characteristic rhythm disturbances (enhanced automaticity with AV block, bidirectional ventricular tachycardia) 2
- Ancillary symptoms including gastrointestinal complaints (anorexia, nausea, vomiting, and diarrhea) 2, 1
- Elevated serum digoxin concentrations (typically >2 ng/mL, though toxicity can occur at lower levels) 2
Important Caveats
Toxicity can occur even when serum digoxin concentration is within the therapeutic range (0.5-1.2 ng/mL), particularly in the presence of hypokalemia, hypomagnesemia, hypothyroidism, or renal dysfunction. 2, 3
Gastrointestinal symptoms serve as warning signs that should prompt evaluation for digoxin toxicity, especially when accompanied by bradycardia or neuropsychological symptoms. 4
In pediatric patients, gastrointestinal symptoms (including diarrhea) are rarely the initial symptoms of overdosage—cardiac arrhythmias typically appear first in children. 1
Management Implications
When diarrhea occurs alongside other symptoms suggestive of digoxin toxicity:
- Immediately discontinue digoxin and initiate continuous cardiac rhythm monitoring. 2
- Correct electrolyte abnormalities, particularly maintaining serum potassium >4.0 mEq/L (ideally 4.0-5.5 mEq/L). 2
- For life-threatening manifestations (sustained ventricular arrhythmias, advanced AV block, severe hyperkalemia), administer digoxin-specific Fab antibody fragments immediately. 2