Experience in Treating Heart Failure, July 28, 1986

Experience in Treating Heart Failure, July 28, 1986

The dosage of digitalis for treating heart failure should be calculated based on the drug's half-life. There are two formulas for calculating the daily excretion rate of digoxin:

Excretion rate (%) = (14 + endogenous creatinine clearance rate) / 5 × 100%

Excretion rate (%) = (11.6 + 20 / creatinine) × 100%

Under normal renal function, the calculated values from these formulas are 31%–33%, or about one-third. Therefore, the daily excretion rate of digoxin can be roughly estimated as one-third. Based on this principle, the formula for calculating the body's digoxin reserve is:

Daily body reserve = (Previous day's body reserve + Current day's dosage) × 2/3

Thus, for digoxin 0.25 mg, taken three times daily, the body reserve after three days of use should be 1 mg.