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Serum digoxin levels in neonates, infants and children with heart disease
Insights
Younger patients under four months had higher serum digoxin levels, regardless of dose. Digoxin dosage and serum levels showed a weak correlation, with few toxic effects observed.
Area of Science:
- Pediatric Pharmacology
- Cardiology
- Clinical Chemistry
Background:
- Digoxin is a crucial medication for treating heart conditions in pediatric patients.
- Understanding optimal digoxin dosage and serum levels is vital for effective treatment and minimizing toxicity.
- Age-related pharmacokinetic differences can influence drug levels in neonates and infants.
Purpose of the Study:
- To investigate the relationship between oral digoxin dosage, serum levels, and patient age in neonates, infants, and children.
- To assess the impact of age on serum digoxin concentrations.
- To evaluate the correlation between digoxin dosage, serum levels, and clinical response, particularly after cardiac surgery.
Main Methods:
- Serum digoxin levels were measured in two groups of pediatric patients receiving high-dose (18-22 microgram/kg/day) and low-dose (<18 microgram/kg/day) oral maintenance digoxin.
- Patients were stratified by age, with a focus on those under four months compared to older individuals.
- Digoxin levels were also monitored before and after cardiac surgery in a subset of patients.
Main Results:
- Patients under four months of age exhibited significantly higher serum digoxin levels compared to older patients in both high-dose (2.6 vs. 1.4 ng/ml) and low-dose (2.2 vs. 1.0 ng/ml) groups.
- A weak correlation was observed between digoxin dosage and serum levels, unaffected by blood urea levels.
- Only two patients displayed toxic manifestations, and postoperative cardiac surgery patients showed decreased pulse rates despite lower digoxin levels, indicating hemodynamic influence.
Conclusions:
- Age is a significant factor influencing serum digoxin levels in pediatric patients, with younger infants requiring careful dosage consideration.
- The relationship between digoxin dosage and serum concentration is not strongly linear and is influenced by factors beyond simple dosage and blood urea.
- Clinical response to digoxin is multifactorial, with hemodynamic status playing a critical role alongside serum drug levels, necessitating individualized treatment approaches.
Abstract:
Serum digoxin levels were measured in 53 neonates and infants receiving 18-22 microgram/kg/day (high dose) oral maintenance digoxin, and 44 neonates, infants and children receiving less than 18 microgram/kg/day (low dose) oral maintenance digoxin. In both groups, patients under four months of age had significantly higher serum digoxin levels than older patients, in the high dose group 2.6 ng/ml compared with 1.4 ng/ml and in the low dose group 2.2 ng/ml compared with 1.0 ng/ml. Correlation between digoxin dosage and serum level was weak and unaffected by blood urea level. Only two patients in the entire series showed toxic manifestations. Sixteen patients had serum digoxin levels measured before and after corrective cardiac surgery while receiving comparable dosages of digoxin. Despite lower serum digoxin levels postoperatively pulse rates fell significantly, illustrating the influence of changing haemodynamic status on the inter-relationships of digoxin dosage, serum levels and clinical response. Recommended dosage regimens are outlined.