DIGOXIN tablet dosage and administration
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Abdurahman Khalil, M.D. [2]
For patient information about Digoxin, click here.
Dosage and Administration
Important Dosing and Administration Information
In selecting a Digoxin Tablets 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.
Consider interruption or reduction in Digoxin Tablets dose prior to electrical cardioversion [see Warnings and Precautions]
Use digoxin solution to obtain the appropriate dose in infants, young pediatric patients, or patients with very low body weight.
Loading Dosing Regimen in Adults and Pediatric Patients
For adults and pediatric patients if a loading dosage is to be given, administer half the total loading dose initially, then ¼ the loading dose every 6 to 8 hours twice, with careful assessment of clinical response and toxicity before each dose. The recommended loading dose is displayed in Table 1.
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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].
The recommended starting maintenance dose in adults and pediatric patients over 10 years old with normal renal function is given in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.
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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 Digoxin Tablets in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.
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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]. The recommended starting maintenance dose for pediatric patients between 5 years and 10 years old is given in Table 4. These recommendations assume the presence of normal renal function.
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Table 5 provides average daily maintenance dose requirements for pediatric patients between 5 and 10 years old (to be given twice daily) with heart failure based on age, lean body weight, and renal function.
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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 Digoxin Tablets dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting Digoxin Tablets and correct post-treatment values by the reported baseline level. Obtain serum digoxin concentrations just before the next scheduled Digoxin Tablets dose or at least
6 hours after the last dose. The digoxin concentration is likely to be 10 to 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).
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References
http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=41c16cff-b03e-405e-a617-d6f45d3ce2bd