Related Experiment Videos
The 24-hour serum digoxin level as a prognosticator of dosage requirement in low-birth-weight (LBW) infants
Insights
Predicting digoxin dosage in low birth weight (LBW) infants is possible using serum digoxin concentrations (SDC). A 24-hour SDC after the first dose strongly correlates with the infant's total body digoxin clearance and future dosage needs.
Area of Science:
- Pharmacokinetics
- Neonatal Medicine
- Pediatric Pharmacology
Background:
- Low birth weight (LBW) infants often require digoxin for cardiac conditions.
- Accurate digoxin dosing is crucial due to narrow therapeutic windows.
- Individualized dosage adjustments are necessary, but predictability remains a challenge.
Purpose of the Study:
- To evaluate the predictability of digoxin dosage requirements in LBW infants.
- To determine the correlation between single serum digoxin concentrations (SDC) and total body digoxin clearance (TBDC).
- To identify optimal time points for SDC measurements for dosage prediction.
Main Methods:
- Studied eleven LBW infants receiving their first digoxin dose.
- Calculated TBDC using computer-fitted biexponential equations from first-dose blood level curves.
- Measured SDCs at various time points (6, 12, and 24 hours) post-dose.
Main Results:
- No significant correlation was found between 6-hour SDCs and TBDC.
- Significant negative correlations were observed between 12-hour (r = -0.53) and 24-hour (r = -0.87) SDCs and TBDC.
- A strong positive correlation (r = 0.88) existed between 24-hour SDCs and the reciprocal of the daily dose required for a target steady-state level.
Conclusions:
- Early serum digoxin concentrations (6-hour) are poor predictors of digoxin dosage requirements in LBW infants.
- Later SDCs, particularly 24-hour concentrations, significantly correlate with TBDC and can predict future digoxin dosage needs.
- A 24-hour SDC is a reliable indicator for adjusting digoxin dosage in LBW neonates.
Abstract:
Eleven LBW infants were studied to assess the predictability of individual digoxin dosage requirement from a single serum digoxin concentration (SDC) at various times within the first dosing interval. The mean and SD of gestational age, weight and postnatal age were 31.6 +/- 3.5 wk, 1.51 +/- 0.47 kg and 3.7 +/- 2.1 days, respectively. Total body digoxin clearance (TBDC) in each infant was calculated from the computer-fitted biexponential equation describing each first-dose blood level curve. There was no correlation between the TBDC (99.5 +/- 37.0 ml/kg/hr) and the 6-hr SDCs (3.1 +/- 0.6 ng/ml) after the first dose (P greater than 0.20). Significant correlation of both 12- and 24-hr SDCs (2.8 +/- 0.6 and 2.3 +/- 0.5 ng/ml) after first dose with TBDC was found (r = -0.53, P less than 0.05 and r = -0.87, P less than 0.005, respectively). Good correlation (r = 0.88) of 1/dose (where dose = mg/kg/day to achieve a mean steady-state level of 2 ng/ml) with the 24-hr SDCs was also observed (P less than 0.005).