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Brand

Digoxin(tablets)

Cardoxin(elixir)

Lanoxin

Pharmacology

A cardiac glycoside, digoxin’s positive inotropic effects promotes movement of calcium from extracellular to intracellular cytoplasm, and inhibits sodium-potassium activated adenosine triphosphatase which increases myocardial contractility and output. It is able to increase diuresis, reduce edema, reduce heart rate, and blood volume. It is also able to reduce pulmonary congestion and venous pressure.

It is absorbed in the small intestine, distributed widely in tissues with the highest levels being in kidneys, heart, intestine, stomach, liver and skeletal muscle. The drug is only slightly metabolized, and is excreted by way of glomerular and tubular secretion.

Indications

Used in CHF due to venous congestion, arrhythmias, and dilated cardiomyopathy.

Drug Interactions or Contraindications

Not recommended to be mixed in with other medications.

Use cautiously in glomerulonephritis and severe pulmonary disease.

The following drugs may decrease digoxin’s absorption: antacids, cimetidine, metoclopramide, neomycin, and some chemotherapy agents.

Digoxin serum levels may increase or its elimination rate decreased, or toxic effects enhanced with the following drugs: diazepam, quinidine, anticholinergics, sumlinylcholine, verapamil, tetracyclines, erythromycin, furosemide, thiazides, glucocorticoids, and laxatives.

For additional information regarding interactions check with a Pharmacist.

Adverse Reactions

*Toxicity:  Narrow margin of safety. Overdosage is a cumulative effect. The most serious of which is low potassium level(hypokalemia).

CNS:  irritability, lethargy

CV:  changes in heart rate, rhythm, irritibility of the heart and mechanics of the heart.

GI:  decreased apetite, abdominal pain, diarrhea, bowel necrosis.

Dosage Recommendations

0.0025 mg/lb , PO , BID  ³

Smaller dosages should be used in animals with hyponatremia(low sodium), hypokalemia(low potassium), hypercalcemia(high calcium), and hypo or hyperthyroidism.

Considerations

Food may delay the drugs absorption but does not alter it.

Store at room temperature, away from light.

Posted on June 23, 2003, 16:05, Last updated on June 10, 2008, 17:06 | Cardiovascular Drugs