【藥品性質提示】 根據 2019 AGS Beers Criteria，本藥品為【潛在不適當用藥 (PIM)】，不建議用於老年人第一線治療。

心律不整、心衰竭 Atrial fibrillation or atrial flutter, Heart failure with reduced ejection fraction (HFrEF)
1. Atrial fibrillation or atrial flutter: control of ventricular response rate in adults with chronic atrial fibrillation
2. HFrEF: mild to moderate (or stage C as recommended by the ACCF/AHA) heart failure in adults

#仿單變更2021

Antiarrhythmic Agent; Cardiac Glycoside:
Supraventricular arrhythmias: Direct suppression of the AV node conduction to increase effective refractory period and decrease conduction velocity.
Heart failure: Inhibition of the Na⁺-K⁺-ATPase pump in myocardial cells, which in turn promotes calcium influx leading to increased contractility.

Absorption
1. Food may delay, but does not affect extent of absorption
2. Bioavailability: 60% to 80%
Distribution
1. Vd: Extensive to peripheral tissues, heart/serum concentration is 70:1
2. Protein binding:~25%
Metabolism
once absorbed, only ~16% is metabolized to 3-beta-digoxigenin, 3-keto-digoxigenin, and glucuronide and sulfate conjugates
Excretion
Mainly in urine, 50-70% as unchanged drug, by glomerular filtration and active tubular secretion
Pharmakodynamics
1. Therapeutic plasma concentrations: (adults) generally 0.5–2 ng/mL.
2. Onset of action: (Heart rate control)1-2 hrs
3. Time to peak: 1-3 hrs
4. Duration: (Adult) 3-4 days

1. Ventricular fibrillation
2. Digitalis intoxication
3. Hypersensitivity to digoxin, other forms of digitalis

C
Although limited experience, the data is lacking association between the drug and congenital defects.

The amount of digoxin available to the infant via breast milk is not likely to be clinically significant. WHO considers digoxin to be compatible with breastfeeding

Common:
GI disturbance, anorexia (the earliest symptom of digoxin overdose), cardiac arrhythmia, conduction defect, blurred vision, halos around bright objects, disturbed color vision (yellow vision)

Administration:
Peak serum concentrations may be decreased if taken with food (containing increased fiber or foods high in pectin)
Atrial fibrillation/flutter: for rate control
  1. (Oral) Maintenance dose: 0.125 to 0.25 mg once daily
Heart failure with reduced ejection fraction (HFrEF):
  1. (Oral) Maintenance dose: 0.125 to 0.25 mg once daily; higher daily doses are rarely necessary
  2. If patient is >70 years of age, has impaired renal function, or has a low lean body mass, low doses (eg, 0.125 mg daily or every other day) should be used initially
Note: Patients with low lean body weight may require lower doses.

Loading dose:(oral)
  1. Neonate(<1.5kg): 25 mcg/kg within 24 hours
  2. Neonate(1.5-2.5kg): 30 mcg/kg within 24 hours
  3. 1-24 months: 45 mcg/kg within 24 hours
  4. 2-5 years of age: 35 mcg/kg within 24 hours
  5. 5-10 years of age: 25 mcg/kg within 24 hours<2021/8/17>
Maintenance dose:
  1. Neonate: 20% of loading dose within 24 hours
  2. 1 month to 10 years of age: 25% of loading dose within 24 hours<2021/8/17>

See more information (Uptodate: Pediatric drug information)

Atrial fibrillation/flutter:
1. Loading dose:
  (1) CrCl >15 mL/minute: No dosage adjustment necessary
  (2) CrCl ≤15 mL/minute: Administer 50% of usual dose
  (3) Hemodialysis, peritoneal dialysis: Use only when rapid ventricular rate control is necessary, reduce to 50% of usual dose
2. Maintenance dose:
  (1) CrCl ≥60 mL/minute: No dosage adjustment necessary
  (2) CrCl 45 to 60 mL/minute: 0.0625 to 0.125 mg once daily
  (3) CrCl 30 to 45 mL/minute: 0.0625 mg once daily
  (4) CrCl <30 mL/minute, hemodialysis, peritoneal dialysis: 0.0625 mg every 48 hours or consider alternative agent
Heart failure:
See more information (Uptodate)

No dosage adjustment necessary.