Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: digoxin
BRAND NAME: Lanoxin
DRUG CLASS AND MECHANISM:
Digoxin increases the strength and vigor of heart contractions, and is useful in
the treatment of heart failure. It is extracted from the leaves of a plant
called digitalis lanata. Digoxin increases the force of contraction of the
muscle of the heart by inhibiting the activity
of an enzyme (ATPase) that controls movement of calcium, sodium and potassium
into heart muscle. Calcium
controls the force of contraction. Inhibiting ATPase increases calcium in heart
muscle and therefore increases the force of heart contractions. Digoxin also
slows electrical conduction between the atria and the ventricles of the heart
and is useful in treating abnormally rapid atrial rhythms such as atrial
fibrillation, atrial flutter, and atrial tachycardia.
(Abnormally rapid atrial rhythms can be caused by
heart attacks, excessive
thyroid hormones,
alcoholism, infections, and many other conditions.) During rapid atrial rhythms,
electrical signals from the atria cause rapid contractions of the ventricles.
Rapid ventricular contractions are inefficient in pumping blood containing
oxygen and nutrients to the body, causing symptoms of weakness, shortness of
breath, dizziness, and even chest pain. Digoxin alleviates these symptoms by
blocking the electrical conduction between the atria and ventricles, thus
slowing ventricular contractions. The FDA approved digoxin in 1975.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets: 0.125, and 0.25 mg; Elixir: 0.05, 0.25, and 0.1
mg/ml.
STORAGE: Digoxin should be stored at room temperature, 59-86 F (15-30 C) and protected from light.
PRESCRIBED FOR: Digoxin is
used for mild to moderate congestive heart failure and for treating an
abnormal
heart rhythm called atrial fibrillation.
DOSING: Digoxin may be taken
with or without food. Digoxin is primarily eliminated by the kidneys; therefore,
the dose of digoxin should be reduced in patients with kidney dysfunction.
Digoxin blood levels are used for adjusting doses in order to avoid toxicity. The usual starting dose is
0.0625-0.25 mg daily depending on age and kidney function. The dose may be
increased every two weeks to achieve the desired response.
DRUG INTERACTIONS: Drugs such
as verapamil (Calan, Verelan, Verelan PM, Isoptin, Isoptin SR, Covera-HS), quinidine (Quinaglute, Quinide), amiodarone (Cordarone), indomethacin (Indocin, Indocin-SR), alprazolam (Xanax, Xanax XR, Niravam), spironolactone (Aldactone), and itraconazole (Sporanox) can increase digoxin
levels and the risk of toxicity. The co-administration of digoxin and
beta-blockers [for example propranolol (Inderal, Inderal LA) or calcium channel blockers (for example, verapamil),
which also reduces heart rate, can cause serious slowing of the heart rate.
Diuretic-induced [for example, by furosemide
(Lasix)] reduction in blood potassium or
magnesium levels may predispose patients to digoxin-induced abnormal heart
rhythms.
Saquinavir (Invirase) and ritonavir (Norvir) increase the amount of digoxin
in the body and may cause digoxin toxicity.
PREGNANCY: There are no
adequate studies in pregnant women.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
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- Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.
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