digoxin

Digoxin is derived from the leaves of a digitalis plant. Digoxin helps make the heart beat stronger and with a more regular rhythm.

Digoxin is used to treat heart failure.

Digoxin is also used to treat atrial fibrillation, a heart rhythm disorder of the atria (the upper chambers of the heart that allow blood to flow into the heart).

Important information

You should not use digoxin if you have ventricular fibrillation (a heart rhythm disorder of the ventricles, or lower chambers of the heart that allow blood to flow out of the heart).

Before taking this medicine

You should not use digoxin if you are allergic to it, or if you have ventricular fibrillation (a heart rhythm disorder of the ventricles, or lower chambers of the heart that allow blood to flow out of the heart).

To make sure digoxin is safe for you, tell your doctor if you have:

• a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• a recent history of heart attack;

• kidney disease;

• a thyroid disorder;

• an electrolyte imbalance (such as low levels of calcium, potassium, or magnesium in your blood); or

• if you are malnourished or have recently been sick with vomiting or diarrhea.

FDA pregnancy category C. It is not known whether digoxin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

See also: Pregnancy and breastfeeding warnings (in more detail)

Digoxin can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Serious side effects may be more likely in older adults and those who are ill or debilitated.

How should I take digoxin?

Take digoxin exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Try to take the medication at the same time every day.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

While using digoxin, you may need frequent blood tests. Your kidney function may also need to be checked.

Use digoxin regularly even if you feel fine or have no symptoms. Get your prescription refilled before you run out of medicine completely.

You should not stop using digoxin suddenly. Stopping suddenly may make your condition worse.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if your next dose is less than 12 hours away. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of digoxin can be fatal.

What should I avoid while taking digoxin?

Avoid becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids. Digoxin overdose can occur more easily if you are dehydrated.

Digoxin side effects

Get emergency medical help if you have any of these signs of an allergic reaction to digoxin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• fast, slow, or uneven heart rate;

• bloody or black, tarry stools;

• blurred vision, yellowed vision; or

• confusion, hallucinations, unusual thoughts or behavior.

Common digoxin side effects may include:

• nausea, vomiting, diarrhea, loss of appetite;

• feeling weak or dizzy;

• headache, weakness, anxiety, depression;

• enlarged breasts in men; or

• mild skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Digoxin dosing information

Usual Adult Dose for Congestive Heart Failure:

Rapid Digitalization with a Loading Dose:
Peak digoxin body stores of 8 to 12 mcg/kg generally provide a therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm.

The loading dose should be administered in several fractions, with approximately half the total given as the first dose. Additional fractions of the total dose may be given at 6 to 8 hour intervals. Careful assessment of the patient"s clinical response should be considered before each additional dose. If the patient"s response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.

Tablets:
Initial: 500 to 750 mcg usually produces a detectable effect in 0.5 to 2 hours with a maximal effect in 2 to 6 hours. Additional doses of 125 to 375 mcg may be given at 6 to 8 hour intervals until clinical evidence of an adequate effect is noted. The usual amount of digoxin tablets that a 70 kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1250 mcg.

Capsules:
Initial: 400 to 600 mcg of digoxin capsules generally produces a detectable effect in 0.5 to 2 hours with a maximal effect in 2 to 6 hours. Additional doses of 100 to 300 mcg may be given cautiously at 6 to 8 hour intervals until clinical evidence of an adequate effect is noted. The usual amount of digoxin capsules that a 70 kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 600 to 1000 mcg.

Injection:
Initial: 400 to 600 mcg of digoxin intravenously usually produces a detectable effect in 5 to 30 minutes with a maximal effect in 1 to 4 hours. Additional doses of 100 to 300 mcg may be given cautiously at 6 to 8 hour intervals until clinical evidence of an adequate effect is noted. The usual amount of digoxin injection that a 70 kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 600 to 1000 mcg. The injectable route is frequently used to achieve rapid digitalization, with conversion to digoxin tablets or digoxin capsules for maintenance therapy.

Maintenance Dose:
The doses of digoxin tablets used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg once daily. In these studies, the digoxin dose has been generally titrated according to the patient"s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg once daily in patients under age 70 with good renal function.

Usual Adult Dose for Atrial Fibrillation:

Peak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects.

Usual Pediatric Dose for Atrial Fibrillation:

Do not give full total digitalizing dose at once. Administer loading doses in several portions, give roughly half the total as the first dose. Give additional fractions of the total dose at 6 to 8 hour intervals (oral) or 4 to 8 hour intervals (parenteral). Divided daily dosing is recommended for infants and young children under 10 years of age.

Parenteral administration should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intravenous administration is preferred over intramuscular injection as it can lead to severe pain at the injection site. If it is necessary to administer the drug by the intramuscular route, it should be injected deep into the muscle followed by massage. No more than 500 mcg should be injected into a single site.

Calculated doses should be based on lean body weight.

Premature:
Digitalizing (Loading) dose: Oral elixir: 20 to 30 mcg/kg; Intravenous: 15 to 25 mcg/kg
Maintenance dose: oral 5 to 7.5 mcg/kg; intravenous 4 to 6 mcg/kg

Full Term:
Digitalizing (Loading) dose: Oral elixir: 25 to 35 mcg/kg; Intravenous: 20 to 30 mcg/kg
Maintenance dose: oral 6 to 10 mcg/kg; intravenous 5 to 8 mcg/kg

1-24 months:
Digitalizing (Loading) dose: Oral elixir: 35 to 60 mcg/kg; Intravenous: 30 to 50 mcg/kg
Maintenance dose: 10 to 15 mcg/kg oral; intravenous 7.5 to 12 mcg/kg

3 to 5 years:
Digitalizing (Loading) dose: Oral elixir: 30 to 40 mcg/kg; Intravenous: 25 to 35 mcg/kg
Maintenance dose: oral 7.5 to 10 mcg/kg; intravenous 6 to 9 mcg/kg

6 to 10 years:
Digitalizing (Loading) dose: Oral elixir: 20 to 35 mcg/kg; Intravenous: 15 to 30 mcg/kg
Maintenance dose: oral 5 to 10 mcg/kg; intravenous 4 to 8 mcg/kg

11 years and older:
Digitalizing (Loading) dose: Oral elixir: 10 to 15 mcg/kg; Intravenous: 8 to 12 mcg/kg
Maintenance dose: oral 2.5 to 5 mcg/kg; intravenous 2 to 3 mcg/kg

What other drugs will affect digoxin?

Other drugs may interact with digoxin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.