BMA Concise Guide to Medicine & Drugs

Digoxin

Brand name Lanoxin

Used in the following combined preparations None

QUICK REFERENCE

Drug group Digitalis drug

Overdose danger rating High

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Digoxin is the most widely used extract of digitalis, a compound obtained from the leaves of the foxglove plant. It is given in the treatment of irregular heart rhythms such as atrial fibrillation or atrial flutter; it may also sometimes be used to treat congestive heart failure.

Digoxin increases the force of the heartbeat making it more effective in pumping blood around the body. This in turn helps to control breathlessness, fluid retention, and tiredness in people with heart failure.

The effective dose of digoxin can be close to the toxic dose and, therefore, treatment needs careful monitoring to prevent toxic doses being reached. A number of adverse effects may indicate that the toxic level is close and should be reported to your doctor.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, liquid, injection.

Frequency and timing of doses Up to 3 x daily (starting dose); once daily, or divided to reduce nausea (maintenance dose).

Adult dosage range Usually 0.0625–0.25mg daily (by mouth), but doses of up to 0.5mg are occasionally used.

Onset of effect Within a few minutes (injection); within 1–2 hours (by mouth).

Duration of action Up to 4 days.

Diet advice Drug may be more toxic if potassium levels are low. Include potassium-rich fruit and vegetables, such as bananas and tomatoes in your diet.

Storage Keep in original container at room temperature out of the reach of children. Protect from light.

Missed dose Take as soon as you remember. If your next dose is due within 8 hours, take a dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor; stopping the drug may lead to worsening of the underlying condition.

OVERDOSE ACTION

Seek immediate medical advice in all cases. Take emergency action if palpitations, severe weakness, chest pain, or loss of consciousness occur.

POSSIBLE ADVERSE EFFECTS

Adverse effects are usually due to high levels of the drug in the blood. Common effects include tiredness, nausea, and loss of appetite. More rarely, confusion, visual disturbance, and palpitations may occur. Any symptoms should be reported to your doctor without delay. If you experience palpitations and/or visual disturbances, you should also stop taking the drug.

INTERACTIONS

General note Many drugs interact with digoxin. Do not take any medication without consulting your doctor or pharmacist.

Diuretics may increase the risk of adverse effects from digoxin if they lower potassium levels.

Ciclosporin and tacrolimus may increase blood levels of digoxin.

Calcium channel blockers and anti-arrhythmic drugs (e.g. amiodarone and quinidine) may increase blood levels of digoxin.

Antacids may reduce the effects of digoxin. The effect of digoxin may increase when antacids are stopped.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have had previous problems with your heart rhythm.

· You have kidney problems.

· You have thyroid trouble.

· You are taking other medicines.

Pregnancy No evidence of risk, but adjustment in dose may be necessary.

Breast-feeding The drug passes into breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 Increased likelihood of adverse effects. Reduced dose may therefore be necessary.

Driving and hazardous work Special problems are unlikely, but do not undertake these activities until you know how digoxin affects you because it can cause tiredness and visual disturbances.

Alcohol No special problems.

PROLONGED USE

No problems expected.

Monitoring Periodic checks on blood levels of digoxin and body salts may be advised.