Lanoxin Dosage

Generic name: digoxin
Dosage form: injection, solution

This dosage information does not include all the information needed to use Lanoxin safely and effectively. See full prescribing information for Lanoxin.

The information at Drugs.com is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Important Dosing and Administration Information

In selecting a LANOXIN dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.

Parenteral administration of digoxin should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intramuscular injection can lead to severe pain at the injection site, thus intravenous administration is preferred. If the drug must be administered by the intramuscular route, it should be injected deep into the muscle followed by massage. For adults, no more than 500 mcg of LANOXIN Injection should be injected into a single site. For pediatric patients, no more than 200 mcg of LANOXIN Injection Pediatric should be injected into a single site.

Administer the dose over a period of 5 minutes or longer and avoid bolus administration to prevent systemic and coronary vasoconstriction. Mixing of LANOXIN Injection and Injection Pediatric with other drugs in the same container or simultaneous administration in the same intravenous line is not recommended.

LANOXIN Injection and Injection Pediatric can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection. The use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin. Immediate use of the diluted product is recommended.

If tuberculin syringes are used to measure very small doses do not flush with the parenteral solution after its contents are expelled into an indwelling vascular catheter to avoid overadministration of digoxin.

Consider interruption or reduction in LANOXIN dose prior to electrical cardioversion [see Warnings and Precautions (5.4)].

Loading Dosing Regimen in Adults and Pediatric Patients

Table 1. Recommended LANOXIN Injection Loading Dose
mcg = microgram
Age Total IV Loading Dose (mcg/kg)
     
Administer half the total loading dose initially,     
then ¼ the loading dose every 6-8 hours twice
Premature 15-25
Full-Term 20-30
1-24 Months 30-50
2-5 Years 25-35
5-10 Years 15-30
Adults and pediatric patients over 10 years      8-12

Maintenance Dosing in Adults and Pediatric Patients Over 10 Years Old

The maintenance dose is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)].

The recommended starting maintenance doses in adults and pediatric patients over 10 years old with normal renal function are given in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.

Table 2. Recommended Starting LANOXIN Injection Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old
mcg = microgram
Age      Total Intravenous Maintenance Dose,     
mcg/kg/day
(given once daily)
Adults and pediatric patients over 10 years      2.4-3.6

Table 3 provides the recommended (once daily) maintenance dose for adults and pediatric patients over 10 years old (to be given once daily) according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):

Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100
(% Daily Loss = 14 + Creatinine clearance/5)

Reduce the dose of LANOXIN in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.

Table 3. Recommended Maintenance Dose (in micrograms given once daily) of LANOXIN Injection in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Function
a  For adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.
For pediatric patients, the modified Schwartz equation may be used. The formula is 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
b  If no loading dose administered
c  The doses listed assume average body composition.
     Corrected     
Creatinine Clearancea
Lean Body Weightc      Number of Days 
Before Steady
State Achievedb
  kg      40       50       60       70       80       90       100   
10 mL/min 64 80 96 112 128 144 160 19
20 mL/min 72 90 108 126 144 162 180 16
30 mL/min 80 100 120 140 160 180 200 14
40 mL/min 88 110 132 154 176 198 220 13
50 mL/min 96 120 144 168 192 216 240 12
60 mL/min 104 130 156 182 208 234 260 11
70 mL/min 112 140 168 196 224 252 280 10
80 mL/min 120 150 180 210 240 270 300 9
90 mL/min 128 160 192 224 256 288 320 8
100 mL/min 136 170 204 238 272 306 340 7

Maintenance Dosing in Pediatric Patients Less Than 10 Years Old

The starting maintenance dose for heart failure in pediatric patients less than 10 years old is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)]. The recommended starting maintenance doses for pediatric patients are given in Table 4. These recommendations assume the presence of normal renal function.

Table 4. Recommended Starting LANOXIN Injection Maintenance Dosage in Pediatric Patients Less Than 10 Years Old
mcg = microgram
Age Dose Regimen,
mcg/kg/dose
     (given TWICE daily)     
Premature           1.9-3.1
Full-Term 3.0-4.5
1-24 Months 4.5-7.5
2-5 Years 3.8-5.3
5-10 Years 2.3-4.5

Table 5 provides average daily maintenance dose requirements for pediatric patients less than 10 years old (to be given twice daily) with heart failure based on age, lean body weight, and renal function.

Table 5. Recommended Maintenance Dose (in micrograms given TWICE daily) of LANOXIN Injection in Pediatric Patients Less Than 10 Years of Agea Based upon Lean Body Weight and Renal Functiona
a  Recommended are doses to be given twice daily.
b  The modified Schwartz equation may be used to estimate creatinine clearance. See footnote a under Table 3.
c  If no loading dose administered.
     Corrected     
Creatinine Clearanceb
Lean Body Weight      Number of Days 
Before Steady
State Achievedc
  kg      5       10       20       30       40       50       60   
10 mL/min 8 16 32 48 64 80 96 19
20 mL/min 9 18 36 54 72 90 108 16
30 mL/min 10 20 40 60 80 100 120 14
40 mL/min 11 22 44 66 88 110 132 13
50 mL/min 12 24 48 72 96 120 144 12
60 mL/min 13 26 52 78 104 130 156 11
70 mL/min 14 28 56 84 112 140 168 10
80 mL/min 15 30 60 90 120 150 180 9
90 mL/min 16 32 64 96 128 160 192 8
100 mL/min 17 34 68 102 136 170 204 7

Monitoring to Assess Safety, Efficacy, and Therapeutic Blood Levels

Monitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.

Serum digoxin levels less than 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.

Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the LANOXIN dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions (7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting LANOXIN and correct post-treatment values by the reported baseline level.

Obtain serum digoxin concentrations just before the next scheduled LANOXIN dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10-25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.

Switching from Intravenous Digoxin to Oral Digoxin

When switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 6).

Table 6. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous LANOXIN
Absolute      Bioavailability      Equivalent Doses (mcg)
LANOXIN Tablets 60-80%    62.5       125       250       500   
LANOXIN Intravenous Injection      100% 50 100 200 400

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