DIGOXIN
(Lanoxin)Standard Prescription
digoxin__mcg PO Q__H (__mcg/kg/24hr)
digoxin__mcg IV Q__H (__mcg/kg/24hr)
digoxin__mcg IV Q__H (__mcg/kg/24hr)
Dosages
**Digitalizing Dose: (rarely indicated - see comments)
Term Infants - 2 years old:
13-17 mcg/kg/dose PO Q8H x 3 doses 10-12 mcg/kg/dose IV Q8H x 3 doses
> 2 years old:
13 mcg/kg/dose PO Q8H x 3 doses 10 mcg/kg/dose IV Q8H x 3 doses
Maintenance Dose:
Start 12 hours after last digitalizing dose.
Term Infants - 2 years old:
10 mcg/kg/24 hr. PO once daily or div. Q12H.
> 2 years old:
8 mcg/kg/24 hr PO once daily or div. Q12H.
Term Infants - 2 years old:
13-17 mcg/kg/dose PO Q8H x 3 doses 10-12 mcg/kg/dose IV Q8H x 3 doses
> 2 years old:
13 mcg/kg/dose PO Q8H x 3 doses 10 mcg/kg/dose IV Q8H x 3 doses
Maintenance Dose:
Start 12 hours after last digitalizing dose.
Term Infants - 2 years old:
10 mcg/kg/24 hr. PO once daily or div. Q12H.
> 2 years old:
8 mcg/kg/24 hr PO once daily or div. Q12H.
Mechanism of Action
Cardiac glycoside, Antiarrythmic agent.
Digoxin inhibits the sodium potassium adenosine triphosphatase (Na+/K+ ATPase), mainly in the myocardium, causing an increase in intracellular sodium levels, resulting in decreased activity of the sodium-calcium exchanger, increasing intracellular calcium.
Increased intracellular Ca++ results in:
1) lengthening of phase 4 and phase 0 of the cardiac action potential, leading to a decrease in heart rate.
2) increase in the release of calcium during each action potential, leading to increased force of contraction of the heart without increasing heart energy expenditure.
Increased intracellular Ca++ results in:
1) lengthening of phase 4 and phase 0 of the cardiac action potential, leading to a decrease in heart rate.
2) increase in the release of calcium during each action potential, leading to increased force of contraction of the heart without increasing heart energy expenditure.
Forms Supplied
tablet: 0.0625 mg, 0.125 mg, 0.25 mg
elixir: 0.05 mg/mL
injection: 0.25 mg/mL (2 mL)
elixir: 0.05 mg/mL
injection: 0.25 mg/mL (2 mL)
Comments
**Digitalizing doses are rarely indicated and should be discussed with the cardiology team prior to administration.
May cause GI upset, poor feeding, failure to thrive, cardiac dysrhythmias.
Monitoring should include serum K+, Mg++, Ca++, serum creatinine and a baseline ECG.
In renal dysfunction, doses should be adjusted.
Switching between IV and PO: IV dose is 0.75 x oral dose - Refer to Therapeutic Drug Monitoring Table (white pages in print copy).
Significant drug interactions exist, especially with drug metabolized by CYP450 and PGP (e.g. amiodarone, propafenone); consult Micromedex for a complete list.
See Therapeutic Drug Monitoring table in Supplementary Materials and References (White pages in print edition)
May cause GI upset, poor feeding, failure to thrive, cardiac dysrhythmias.
Monitoring should include serum K+, Mg++, Ca++, serum creatinine and a baseline ECG.
In renal dysfunction, doses should be adjusted.
Switching between IV and PO: IV dose is 0.75 x oral dose - Refer to Therapeutic Drug Monitoring Table (white pages in print copy).
Significant drug interactions exist, especially with drug metabolized by CYP450 and PGP (e.g. amiodarone, propafenone); consult Micromedex for a complete list.
See Therapeutic Drug Monitoring table in Supplementary Materials and References (White pages in print edition)
References
242, 243
Last Edited
2022-06-18 17:22:59