The body’s handling of digoxin can be affected by many different patient-specific factors. Some of the possible effects are small, so anticipatory dose adjustment might not be required, but others should be considered before initial dosing [see Clinical Pharmacology (12.2) and Drug Interactions (7)].

Both adults and pediatric patients with abnormal renal function need to have the dose of digoxin proportionally reduced. Recommended maintenance doses based upon lean body weight and renal function are listed in Table 3. Developmental changes in pediatric renal function were factored into Table 3. However, age-related and other changes in adult renal function were not.

The volume of distribution of digoxin is proportional to lean body weight and doses listed in Table 3 assume average body composition. The dose of digoxin must be reduced in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.

###  Table 3: Usual Maintenance Dose1,2 Requirements (mcg) of Digoxin Based upon Age, Lean Body Weight and Renal Function

  1. The doses are rounded to whole numbers.
  2. Twice daily dosing is recommended for pediatric patients under 10 years of age. Once daily dosing is recommended for pediatric patients above 10 years of age and adults.
  3. Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or pediatric patients. For pediatric patients, the modified Schwartz equation may be used as listed below. The formula was based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2  body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys. GFR (mL/min/1.73 m2) = (k x Height)/Scr.



Determination of the target dose in milliliters of Digoxin Oral Solution based on body weight is shown in Table 4. Provided is the volume required per dose, NOT per day.

###  Table 4: Dosea in Milliliters

a Recommended dosing regimen for pediatric patients under 10 years of age is twice daily. Recommended dosing regimen for pediatric patients over 10 years of age and adults is once daily.

b Use calibrated oral syringe for measurement. In the case of required volume less than 0.1 mL, a separate device is recommended for adequate measurement.

On the left side of the chart, locate the patient’s weight in kilograms. At the top of the chart, identify which dose in mcg/kg will be used for this patient. The block on the chart at which the two rows (weight and target dose) intersect is the milliliter amount that should be given to the patient.

The monitoring described in Section 2.2 may suggest increases or decreases in digoxin doses. Additional monitoring, and in some cases anticipatory dose adjustment, may be indicated around the time of various changes to the patient including:

  * normal development through childhood;
  * concomitant drug use should be considered when adjusting the estimated digoxin dose [see Drug Interactions (7)];
  * new co-administration of an antibiotic, especially if the patient had required high doses of digoxin in order to achieve modest serum concentrations, raising the suspicion that a substantial fraction of administered digoxin was being destroyed by colonic bacteria; and
  * changes in renal function [see Table 3: Usual Maintenance Dose Requirements (mcg) of Digoxin above].