What is the pharmacokinetics of digoxin?
Digoxin is extensively distributed in the tissues, as reflected by the large volume of distribution. High concentrations are found in the heart and kidneys, but the skeletal muscles form the largest digoxin storage. The half-life of elimination in healthy persons varies between 26 and 45 hours.
What is the pharmacodynamics of digoxin?
Mechanism of action Digoxin binds to and inhibits the sodium/potassium-ATPase (sodium pump) within the plasma membrane of cardiac myocytes. This inhibition increases the intracellular sodium content which in turn increases the intracellular calcium content which leads to increased cardiac contractility.
Which drug increases the bioavailability of digoxin?
Certain antibiotics including sulphasalazine, neomycin and aminosalicylic acid reduce digoxin absorption while others, including erythromycin and tetracycline, increase the bioavailability of digoxin in some patients.
Does digoxin undergo first pass metabolism?
Digoxin is not strongly influenced by first pass metabolism or hepatic metabolism. While no significant decrease occurs in phase II metabolism, there is a decrease in clearance of drugs metabolised by phase I pathways [9].
How digoxin works in the body?
Digoxin is a type of drug called a cardiac glycoside. Their function is to slow your heart rate down and improve the filling of your ventricles (two of the chambers of the heart) with blood. For people with atrial fibrillation, where the heart beats irregularly, a different volume of blood is pumped out each time.
What is the bioavailability of digoxin?
The bioavailability of orally administered digoxin is approximately 63 % in tablet form and 75 % as oral solution.
What is the mechanism of action of digoxin in heart failure?
Mechanism of Action Digoxin induces an increase in intracellular sodium that will drive an influx of calcium in the heart and cause an increase in contractility. Cardiac output increases with a subsequent decrease in ventricular filling pressures.
Which drug is contraindicated with digoxin?
Other medications can affect the removal of digoxin from your body, which may affect how digoxin works. Examples include azole antifungals (such as itraconazole), dronedarone, lapatinib, macrolide antibiotics (such as clarithromycin, erythromycin), propafenone, rifampin, St. John’s wort, among others.
Where is digoxin metabolized?
A small fraction of digoxin is metabolized by the liver and approximately 8% undergoes an enterohepatic cycle. The elimination half-life of digoxin is long.
Where does digoxin metabolize?
What enzyme metabolizes digoxin?
It is primarily metabolized through the CYP2C19 enzyme, a member of the P450 mixed-function oxidase group, although a minor pathway of metabolism is through CYP3A4, another P450 enzyme. Digoxin is primarily metabolized outside the P450 system, but a minor pathway of metabolism is by CYP3A4.