The effect of calcium in water hardness on digoxin plasma levels in an experimental rat model.

Background: Digoxin is a drug for ventricular rate control in atrial fibrillation (AF). The major challenge in digoxin therapy is to adjust the appropriate concentration range for this drug due to its narrow therapeutic index. Unique physiochemical properties of drinking water affect the pharmacological actions and delivery of drugs to the body whether they are administered orally, topically, or by injection.