What plant is similar to digoxin (digitalis) for treating heart conditions?

Plants Similar to Digoxin for Treating Heart Conditions

Foxglove (Digitalis purpurea) is the primary plant similar to digoxin for treating heart conditions, containing natural cardiac glycosides that have the same therapeutic and toxic effects as the medication digoxin. 1

Natural Sources of Cardiac Glycosides

Cardiac glycoside compounds similar to digoxin can be found in several plants and some animal sources:

1. Foxglove (Digitalis purpurea) - The original and primary source of digoxin and digitoxin 2, 3
2. Grecian foxglove (Digitalis lanata) - The specific species from which commercial digoxin is extracted 2, 4
3. Yellow oleander (Thevetia peruviana/Cascabela thevetia) - Contains cardiac glycosides with similar effects 1, 5
4. Lily-of-the-valley (Convallaria majalis) - Contains cardiac glycosides 4
5. Bufo toad venom - Contains bufadienolides, which are cardiac glycosides 1, 4

Mechanism and Effects

These plants contain cardioactive steroids that:

• Inhibit the Na+/K+-ATPase pump in cardiac cells
• Increase cardiac contractility (positive inotropic effect)
• Slow heart rate (negative chronotropic effect)
• Have a very narrow therapeutic window 3

Clinical Considerations and Warnings

Toxicity Risk

Cardiac glycoside poisoning from these plants can cause:

• Gastrointestinal symptoms (nausea, vomiting, diarrhea)
• Confusion
• Hyperkalemia
• Cardiac conduction abnormalities:
  • Atrioventricular nodal block
  • Ventricular tachycardia
  • Ventricular fibrillation
  • Asystole 1

Misidentification Dangers

There have been numerous cases of accidental poisoning due to plant misidentification:

• Foxglove leaves are frequently mistaken for comfrey (Symphytum officinale) leaves 6, 5
• Foxglove has also been confused with borage (Borago officinalis) 7
• These misidentifications can lead to life-threatening cardiac toxicity and death 6, 7

Treatment of Poisoning

For cardiac glycoside poisoning from these plants:

1. First-line treatment: Administration of digoxin-specific antibody fragments (digoxin-Fab) is recommended for severe toxicity 1
2. Dosing of digoxin-Fab depends on the amount ingested or serum levels 1
3. Monitoring: Serum potassium levels (hyperkalemia indicates severe poisoning) 1
4. Supportive measures:
   • Atropine for bradydysrhythmias
   • Electrical pacing for refractory bradydysrhythmias
   • Antiarrhythmic medications (lidocaine, phenytoin) for ventricular dysrhythmias until digoxin-Fab can be administered 1

Current Medical Use

While these plants contain active cardiac glycosides, modern medicine uses pharmaceutical-grade digoxin rather than plant preparations due to:

1. Standardized dosing and potency
2. Reduced risk of toxicity
3. Better monitoring capabilities

Digoxin is primarily used in:

• Heart failure with reduced ejection fraction (HFrEF)
• Atrial fibrillation with rapid ventricular response, especially when associated with hypotension 3

Important Caution

Self-medication with these plants is extremely dangerous due to their narrow therapeutic window and high toxicity potential. Multiple fatalities have been reported from both intentional and accidental ingestion of foxglove and similar plants 6, 5, 7.

Healthcare providers should educate patients about the dangers of using wild plants as cardiac medications and the importance of proper plant identification for those who forage for edible plants.