DIGOXIN - a patient's guide
Abstract
BRAND: Lanoxin
USE: heart failure (with atrial fibrillation)
This medicine is called a cardiac glycoside which is indicated for heart failure, especially in patients with atrial fibrillation (heart 'flutter'). Digoxin has complex activity, where it increases the contraction force of the heart but also slows the rate at which the heart pumps (useful in fibrillation).
It also has a very low therapeutic index, because there is a narrow difference between optimal therapeutic dose and toxicity so special care is taken by your doctor when prescribing digoxin.
Caution:
- Previous digoxin (digitallis) toxicity
- Elderly (special care with kidney impairment)
- Hypokalaemia (low potassium levels causes toxicity)
- Recent MI (heart attack)
- Hypothyroidism
- Pregnancy and breast-feeding (discuss with doctor)
Side effects:
Usually dose-related: anorexia (loss of appetite), abdominal pain, stomach upset (nausea, diarrhoea), headache, fatigue, drowsiness, mind disturbances (confusion, delirium, hallucinations).
Overdose: heart block and arrhythmias (disturbances in the rhythm of the heart).
Interactions:
Increased toxicity with quinine, calcium-channel blockers, anti-arrthymias and possibly ACE-Inhibitors. Hypokalemia (low potassium levels) associated with diuretics, lithium and corticosteroids give rise to increased toxicity. Antacids and anion-exchange resins impair absorption of digoxin.
Patient information:
- Follow the instructions carefully on the label of this medicine
- Do not stop taking this medicine unless directed by your doctor
- Food: take with food if this medicine upsets your stomach or as directed
- Antacids: take 6 hours apart to prevent impaired absorption
- Missed dose: take the next dose as soon as you remember (don't double dose)
- Avoid taking other medicines unless directed by your doctor/pharmacist
- Regular monitoring of plasma-digoxin levels maybe needed if you are on diuretic therapy (discuss with doctor)
- Contact your doctor or seek urgent medical help if side effects occur or overdose is suspected.