General High Alert Medication: This medication bears a heightened risk of causing significant patient harm when it is used in error. **BEERS Drug** Pronunciation: Trade Name[s] Ther. Class. antiarrhythmics inotropics Pharm. Class. digitalis glycosides Indications Action Therapeutic Effect[s]: Increased cardiac output [positive inotropic effect] and slowing of the heart rate [negative
chronotropic effect]. Pharmacokinetics
di-jox-in
Absorption: 60–80% absorbed after oral administration of tablets; 70–85% absorbed after administration of elixir; 80% absorbed from IM sites [IM route not recommended due to pain/irritation].
Distribution: Widely distributed; crosses placenta and enters breast milk.
Metabolism and Excretion: Excreted almost entirely unchanged by the kidneys.
Half-life: 36–48 hr [↑ in renal impairment].
TIME/ACTION PROFILE [antiarrhythmic or inotropic effects, provided that a loading dose has been given]
| Digoxin–PO | 30–120 min | 2–8 hr | 2–4 days† |
| Digoxin–IM | 30 min | 4–6 hr | 2–4 days† |
| Digoxin–IV | 5–30 min | 1–4 hr | 2–4 days† |
Contraindication/Precautions
Contraindicated in:
- Hypersensitivity;
- Uncontrolled ventricular arrhythmias;
- AV block [in absence of pacemaker];
- Idiopathic hypertrophic subaortic stenosis;
- Constrictive pericarditis;
- Known alcohol intolerance [elixir only].
Use Cautiously in:
- Hypokalemia [↑ risk of digoxin toxicity];
- Hypercalcemia [↑ risk of toxicity, especially with mild hypokalemia];
- Hypomagnesemia [↑ risk of digoxin toxicity];
- Diuretic use [may cause electrolyte abnormalities including hypokalemia and hypomagnesemia];
- Hypothyroidism;
- Myocardial infarction;
- Renal impairment [dose ↓ required];
- Obesity [base dose on ideal body weight];
- OB: Monitor neonates for signs/symptoms of digoxin toxicity; monitor levels in mother during pregnancy as levels may fluctuate during pregnancy and post-partum periods; may lead to ↑ risk of arrhythmias during labor and delivery;
- Lactation: Similar concentrations in serum and breast milk result in subtherapeutic levels in infant, use with caution;
- Geri: Very sensitive to toxic effects; dose adjustments required for age-related ↓ in renal function and body weight.
Adverse Reactions/Side Effects
CV: ARRHYTHMIAS, bradycardia, ECG changes, AV block, SA block
EENT: blurred vision, yellow or green vision
GI: anorexia, nausea, vomiting, diarrhea
Hemat: thrombocytopenia
Metabolic: electrolyte imbalances with acute digoxin toxicity
Neuro: fatigue, headache, weakness.
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
Interactions
Drug-Drug
- Thiazide and loop diuretics, piperacillin/tazobactam, amphotericin B, corticosteroids, and excessive use of laxatives may cause hypokalemia which may ↑ risk of toxicity.
- Quinidine and ritonavir may ↑ levels and lead to toxicity; ↓ digoxin dose by 30–50%.
- Amiodarone may ↑ levels and lead to toxicity; ↓ digoxin dose by 50%.
- Cyclosporine, itraconazole, mirabegron, propafenone, quinine, spironolactone, and verapamil may ↑ levels and lead to toxicity; serum level monitoring/dose ↓ may be required.
- Levels may be ↓ by some antineoplastics [ bleomycin, carmustine, cyclophosphamide, cytarabine, doxorubicin, methotrexate, procarbazine, vincristine ], activated charcoal, cholestyramine, colestipol, metoclopramide, penicillamine, rifampin, or sulfasalazine.
- In a small percentage [10%] of patients gut bacteria metabolize digoxin to inactive compounds macrolide anti-infectives [ erythromycin, azithromycin, clarithromycin ] and tetracyclines , by killing these bacteria, will cause ↑ levels and toxicity; dose may need to be ↓ for up to 9 wk.
- Additive bradycardia may occur with beta blockers, diltiazem, verapamil, clonidine, ivabradine, and other antiarrhythmics [ quinidine, disopyramide ].
- Concurrent use of sympathomimetics may ↑ risk of arrhythmias.
- Thyroid hormones may ↓ therapeutic effects.
Drug-Natural Products:
- Licorice and stimulant natural products [ aloe ] may ↑ risk of potassium depletion.
- St. John's wort may ↓ levels and effect.
Drug-Food:
Concurrent ingestion of a high-fiber meal may ↓ absorption. Administer digoxin 1 hr before or 2 hrs after such a meal.
Route/Dosage
For rapid effect, a larger initial loading/digitalizing dose should be given in several divided doses over 12–24 hr. Maintenance doses are determined for digoxin by renal function. All dosing must be evaluated by individual response. In general, doses required for atrial arrhythmias are higher than those for inotropic effect.
IV IM [Adults]: Digitalizing dose– 0.5–1 mg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Children >10 yr]: Digitalizing dose– 8–12 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Children 5–10 yr]: Digitalizing dose– 15–30 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Children 2–5 yr]: Digitalizing dose– 25–35 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Children 1–24 mo]: Digitalizing dose– 30–50 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Infants –full term]: 20–30 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
IV IM [Infants –premature]: Digitalizing dose– 15–25 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals.
PO [Adults]: Digitalizing dose– 0.75–1.5 mg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 0.125–0.5 mg/day depending on patient's lean body weight, renal function, and serum level.
PO Geriatric Patients: Initial daily dose should not exceed 0.125 mg.
PO [Children >10 yr]: Digitalizing dose– 10–15 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 2.5–5 mcg/kg given daily as a single dose.
PO [Children 5–10 yr]: Digitalizing dose– 20–35 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 5–10 mcg/kg given daily in 2 divided doses.
PO [Children 2–5 yr]: Digitalizing dose– 30–40 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 7.5–10 mcg/kg given daily in 2 divided doses.
PO [Children 1–24 mo]: Digitalizing dose– 35–60 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 10–15 mcg/kg given daily in 2 divided doses.
PO [Infants –full term]: Digitalizing dose– 25–35 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 6–10 mcg/kg given daily in 2 divided doses.
PO [Infants –premature]: Digitalizing dose– 20–30 mcg/kg given as 50% of the dose initially and one quarter of the initial dose in each of 2 subsequent doses at 6–12 hr intervals. Maintenance dose– 5–7.5 mcg/kg given daily in 2 divided doses.
Availability [generic available]
Elixir [lime flavor]: 0.05 mg/mL
Cost:
Generic: $42.10/60 mL
Solution for injection: 0.25 mg/mL
Solution for injection [pediatric]: 0.1 mg/mL
Tablets: 0.0625 mg, 0.125 mg, 0.25 mg
Cost:
Generic: All strengths $27.75/10
Assessment
- Monitor apical pulse for 1 full min before administering. Withhold dose and notify health care professional if pulse rate is