Small molecule
PubChem CID 2724385
Digoxin
Lanoxin
- Mechanism of action
- Na+/K+-ATPase inhibitor (positive inotrope)
- In plain language
- Blocks a pump on heart muscle cells that helps them contract, so the heart squeezes harder with each beat and slows down at the same time.
- How it works
- Digoxin binds to and inhibits the sarcolemmal Na+/K+-ATPase in myocardial cells, reducing the outward sodium gradient and secondarily slowing the Na+/Ca2+ exchanger. This raises intracellular calcium availability during systole, producing a positive inotropic effect (increased force and velocity of myocardial contraction) without a corresponding rise in myocardial oxygen demand. Digoxin also enhances vagal tone and baroreceptor sensitivity at the SA and AV nodes, slowing conduction velocity and heart rate — the basis for its use in rate control of atrial fibrillation. At toxic concentrations this same ion-pump inhibition instead promotes increased automaticity, which underlies digoxin's narrow therapeutic index.
- Therapeutic applications
- Indicated for the treatment of mild to moderate heart failure in adults, where it increases left ventricular ejection fraction and improves heart failure symptoms; for increasing myocardial contractility in pediatric patients with heart failure; and for control of resting ventricular rate in adult patients with chronic atrial fibrillation.
- Class
- Small molecule
- Therapeutic area
- Cardiovascular
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