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Foxglove, Follow Your Heart, But Don’t Touch
The original heart medicine, Digitalis, was made by Foxglove!
This plant contains toxic cardiac glycosides. Pharmacies produced digoxin using a leaf from a foxglove before they could manufacture this drug.
Serious toxicity is uncommon unless intentionally ingested as food or a suicide attempt.
Toxic Dose
The amount that causes toxicity is not well established. Concentrations of toxic glycosides can vary with climate, growing conditions, season, age, and parts of the plant.
Digoxin is known to have a narrow therapeutic window, and one can easily move from therapeutic to toxic dose through slow elimination and metabolism or through interactions with other drugs.
Pharmacokinetics
The bioavailability (the amount of the drug that enters the circulation when introduced into the body and, therefore, is able to have an active effect) of glycosides from a dried Digitalis leaf is approximately 20–40%.
Elimination half-life (the time it can take to remove half the drug from the body) can be up to 7 days. It takes 5 half-lives for a drug to be considered cleared from the body, so you can see this could take quite some time.
