digoxin

Drug Name

Generic Name : digoxin

Brand Name: Digitek, Lanoxicaps, Lanoxin

Classification: Cardiac glycoside, Cardiotonic

Pregnancy Category C

Dosage & Route
  • Patient response is quite variable. Evaluate patient carefully to determine the appropriate dose.

ADULTS

  • Loading dose, 0.75–1.25 mg PO or 0.125–0.25 mg IV. Maintenance dose, 0.125–0.25 mg/day PO.
  • Lanoxicaps capsules
  • Loading dose, 0.4–0.6 mg PO. Maintenance dose, 0.1 –0.3 mg/day PO.

PEDIATRIC PATIENTS

Loading dose:

 Age  Oral (mcg/kg)  IV (mcg/kg)
 Premature  20–30  15–25
 Neonate  25–35  20–30
 1–24 mo  35–60  30–50
 2–5 yr  30–40  25–35
 5–10 yr  20–35   15–30
> 10 yr  10–15  8–12

Maintenance dose, 20%–30% of loading dose in divided daily doses. Usually 0.125–0.5 mg/day PO; 20%–30% for premature babies.

GERIATRIC PATIENTS WITH IMPAIRED RENAL FUNCTION

 Creatinine Clearance (mL/min)  Dose
 10–25  0.125 mg/day
 26–49  0.1875 mg/day
 50–79  0.25 mg/day
Therapeutic actions
  • Digoxin is a cardiac glycoside which has positive inotropic activity characterized by an increase in the force of myocardial contraction. It also reduces the conductivity of the heart through the atrioventricular (AV) node. Digoxin also exerts direct action on vascular smooth muscle and indirect effects mediated primarily by the autonomic nervous system and an increase in vagal activity.
Indications
  • CHF
  • Atrial fibrillation
Adverse effects
  • Extra beats, anorexia, nausea and vomiting. Diarrhoea in elderly, confusion, dizziness, drowsiness, restlessness, nervousness, agitation and amnesia, visual disturbances, gynaecomastia, local irritation (IM/SC inj), rapid IV admin may lead to vasocostriction and transient hypertension.
  • Potentially Fatal: Cardiac arrhythmias in combination with heart block.
Contraindications
  • Digitalis toxicity, ventricular tachycardia/fibrillation, obstructive cardiomyopathy. Arrhythmias due to accessory pathways (e.g. Wolff-Parkinson-White syndrome).
Nursing considerations
Assessment
  • History: Allergy to digitalis preparations, ventricular tachycardia, ventricular fibrillation, heart block, sick sinus syndrome, IHSS, acute MI, renal insufficiency, decreased K+, decreased Mg2+ increased Ca2+, pregnancy, lactation
  • Physical: Weight; orientation, affect, reflexes, vision; P, BP, baseline ECG, cardiac auscultation, peripheral pulses, peripheral perfusion, edema; R, adventitious sounds; abdominal percussion, bowel sounds, liver evaluation; urinary output; electrolyte levels, LFTs, renal function tests
Interventions
  • WARNING: Monitor apical pulse for 1 min before administering; hold dose if pulse < 60 in adult or < 90 in infant; retake pulse in 1 hr. If adult pulse remains < 60 or infant < 90, hold drug and notify prescriber. Note any change from baseline rhythm or rate.
  • Take care to differentiate Lanoxicaps from Lanoxin; dosage is very different
  • Check dosage and preparation carefully.
  • Avoid IM injections, which may be very painful.
  • Follow diluting instructions carefully, and use diluted solution promptly.
  • Avoid giving with meals; this will delay absorption.
  • Have emergency equipment ready; have K+ salts, lidocaine, phenytoin, atropine, and cardiac monitor readily available in case toxicity develops.
  • WARNING: Monitor for therapeutic drug levels: 0.5–2 ng/mL.
Teaching points
  • Do not stop taking this drug without notifying your health care provider.
  • Take pulse at the same time each day, and record it on a calendar (normal pulse for you is___; call your health care provider if your pulse rate falls below ____.)
  • Weigh yourself every other day with the same clothing and at the same time. Record this on the calendar.
  • Do not start taking any prescription or over-the-counter products without talking to your health care provider. Some combinations may increase the risk of digoxin toxicity and may put you at risk of adverse reactions.
  • Wear or carry a medical alert tag stating that you are on this drug.
  • Have regular medical checkups, which may include blood tests, to evaluate the effects and dosage of this drug.
  • Report unusually slow pulse, irregular pulse, rapid weight gain, loss of appetite, nausea, diarrhea, vomiting, blurred or “yellow” vision, unusual tiredness and weakness, swelling of the ankles, legs or fingers, difficulty breathing.