Cardiac Treatment: Dose Adjustments for Dogs & Cats on

Heart failure is often associated with a decline in the heart's ability to contract. Medications that stimulate heart contraction are known as cardiac glycosides or positive inotropes. These drugs work by enhancing the availability of calcium to the myocardium.

Digoxin is a type of inotropic medication, classified as a cardiac glycoside, which was originally derived from the foxglove plant.

Digoxin can boost the heart's contractility, thereby increasing the volume of blood pumped from the heart. This effect is moderate in nature.

Digoxin also reduces nerve stimulation to the heart, which typically leads to an increased heart rate. The less stimulation, the slower the heart rate becomes.

Digoxin is a prescription medication that can only be obtained from a veterinarian or prescribed by one.

The formulations of Digoxin include:

Human formulations: Lanoxin® (ElkinsSinn), Lanoxicaps® and various generics

Veterinary formulations: Cardoxin® (Evsco) and various generics

Digoxin's Uses in Cats and Dogs

1. Digoxin is used to treat heart failure and various cardiac arrhythmias, particularly atrial fibrillation. It can be used in combination with other medications to achieve this purpose.

2. While Digoxin cannot extend life, it can alleviate the symptoms of heart failure.

3. It is best to monitor the effective use of the drug through blood tests measuring digoxin levels in the blood.

Cautionary Notes and Side Effects

1. Generally, digoxin prescribed by a veterinarian is safe and effective, but the drug can also cause side effects in some animals.

2. Digoxin should not be administered to animals known to be allergic to the drug.

3. Animals with moderate to severe kidney failure, severe lung disease, and certain heart conditions (such as pericarditis) should avoid using digoxin.

4. Caution is essential when using digoxin, as the toxic concentration is very similar to the therapeutic concentration.

5. Digoxin may interact with other medications. Consult your veterinarian to determine if other medications your pet is taking will interact with digoxin. These include: cimetidine, antacids, certain antibiotics, and thyroid replacement therapy. Many drugs can interact with digoxin, leading to increased blood concentrations and a risk of toxic reactions. Examples include diazepam, verapamil, and quinidine.

6. High doses of digoxin can cause adverse reactions, including arrhythmias, loss of appetite, vomiting, and diarrhea.

Dosage Information for Digoxin

1. Dosage for dogs is typically twice daily, at a rate of 0.00125 to 0.0015 mg per pound of body weight (0.0025 to 0.003 mg/kg).

2. For cats, it is usually 1/4 of a tablet, containing 0.125 mg, administered every other day.

3. The duration of treatment depends on the treatment situation and the pet's response to the medication. Even if your pet seems to have recovered, it is crucial to complete the full course of treatment unless the veterinarian provides specific instructions.