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Digoxin Injection is frequently used to achieve rapid digitalization, with conversion to digoxin tablets or Digoxin Solution in Capsules for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see table, CLINICAL PHARMACOLOGY). Maintenance Dosing: The doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been gen-erally titrated according to the patient's age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal func-tion, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response. Text Continues Below
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (+ SD) serum digoxin concentrations at 1 month and 12 months were 1.01 + 0.47 ng/ mL and 0.97 + 0.43 ng/ mL, respectively.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use: Maintenance Dose = Peak Body Stores (i. e., Loading Dose) x % Daily Loss/ 100 Where: % Daily Loss = 14 + Ccr/ 5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m 2 body surface area.) Table 5 provides average daily maintenance dose requirements of digoxin tablets for patients with heart failure based upon lean body weight and renal function: Page: << Prev | 1 | 2 | 3 | 4 | 5 | Next >>
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