• you are allergic to any ingredient in Lanoxin or other digitalis medicines
• you have beriberi heart disease
• you have certain types of heart rhythm problems, such as ventricular fibrillation.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Lanoxin. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have severe heart failure, inflammation of the heart, coronary artery disease, heart attack, heart block, extra heart beats (PVCs), certain abnormal heart rhythms, or fainting due to a heart problem
• if you have severe kidney, liver, or lung problems, or a thyroid problem
• if you have low blood levels of calcium, magnesium, or potassium, or high blood levels of potassium or calcium.

Some medicines may interact with Lanoxin. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Amiodarone, amphotericin B, anticholinergics (eg, propantheline), beta-blockers (eg, propranolol), bupivacaine, calcium, certain stimulants (eg, albuterol, amphetamine, pseudoephedrine), cyclosporine, diltiazem, diphenoxylate, diuretics (eg, hydrochlorothiazide, furosemide), indomethacin, itraconazole, macrolides (eg, erythromycin), propafenone, quinidine, quinine, spironolactone, succinylcholine, tetracyclines (eg, doxycycline), thioamines (eg, methimazole), or verapamil because they may increase the risk of Lanoxin's side effects, especially on the heart
• Acarbose, certain anticancer medicines, cholestyramine, colestipol, kaolin-pectin, metoclopramide, penicillamine, rifampin, sulfasalazine, or thyroid hormones (eg, levothyroxine) because they may decrease Lanoxin's effectiveness
• Oral aminoglycosides (eg, neomycin) because the actions and side effects of Lanoxin may be increased or decreased
• Spironolactone because it may interfere with certain lab tests for digoxin blood levels and give false readings.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Lanoxin may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Lanoxin may cause dizziness or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use Lanoxin with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• Tell your doctor or dentist that you take Lanoxin before you receive any medical or dental care, emergency care, or surgery.
• Lab tests, including electrocardiogram (ECG), electrolytes, and blood digoxin levels, may be performed while you use Lanoxin. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Use Lanoxin with caution in the elderly; they may be more sensitive to its effects.
• Use Lanoxin with extreme caution in infants who are premature or immature; they may be more sensitive to its effects.
• Poisoning may occur in children who accidently swallow Lanoxin or receive too much medicine. In case of an overdose, call a doctor or poison control center right away.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Lanoxin while you are pregnant. Lanoxin is found in breast milk. If you are or will be breast-feeding while you use Lanoxin, check with your doctor. Discuss any possible risks to your baby.

Check with your doctor if any of these most common side effects persist or become bothersome:

Diarrhea; nausea.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blurred vision, yellow vision, or other vision changes; confusion; fast, slow, or irregular heartbeat; hallucinations; mood or mental changes (eg, depression); severe or persistent nausea, vomiting, or stomach pain; unusual bruising or bleeding; unusual tiredness or weakness.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.