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

Lanoxin is used to treat heart failure.

Lanoxin 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).

You should not use Lanoxin 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).

Take Lanoxin exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Try to take oral Lanoxin at the same time every day.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

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

Lanoxin injection is given as a shot into a muscle, or as an infusion into a vein. A healthcare provider will give you this injection if you are unable to take the medicine by mouth.

Your blood pressure and heart rate will need to be checked daily.

You may need frequent blood tests. Your kidney function may also need to be checked.

You should not stop taking Lanoxin suddenly. Stopping suddenly may make your condition worse.

Store at room temperature away from moisture and heat.

Usual Adult Dose of Lanoxin 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.

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 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.

You should not use Lanoxin if you are allergic to digoxin, 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 Lanoxin is safe for you, tell your doctor if you have ever had:

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

• a heart attack;

• slow heartbeats that have caused you to faint;

• Wolff-Parkinson-White Syndrome (sudden fast heartbeats);

• kidney disease;

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

• a thyroid disorder; or

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

Tell your doctor if you are pregnant. It is not known whether digoxin will harm an unborn baby. However, having heart failure or atrial fibrillation during pregnancy may cause complications such as premature birth or low birth weight, or risk of death in both mother and baby. The benefit of treating heart problems with digoxin may outweigh any risks to the baby.

It may not be safe to breast-feed while using Lanoxin. Ask your doctor about any risk.

Take the medicine as soon as you can, but skip the missed dose if your next dose is due in less than 12 hours. Do not take two doses at one time.

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

Overdose symptoms may include nausea, vomiting, loss of appetite, and feeling tired.

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.

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

Call your doctor at once if you have:

• nausea, vomiting, diarrhea, stomach pain;

• fast, slow, or uneven heart rate;

• a light-headed feeling, like you might pass out;

• bloody or black, tarry stools;

• confusion, weakness, hallucinations, unusual thoughts or behavior;

• breast swelling or tenderness;

• blurred vision, yellowed vision; or

• (in babies or children) stomach pain, weight loss, growth delay, behavior changes.

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

Common Lanoxin side effects may include:

• nausea, diarrhea;

• feeling weak or dizzy;

• headache, weakness, anxiety, depression; or

• 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.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can interact with digoxin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.