Pharmacokinetics of tramadol in children after i.v. or caudal epidural administration

Area of Science:

• Pharmacology
• Pediatric Anesthesiology
• Pain Management

Background:

• Tramadol is a widely used analgesic in pediatric patients.
• Understanding its pharmacokinetic profile is crucial for safe and effective pain management.
• Previous studies have established tramadol pharmacokinetics in adults, but data in children are less extensive.

Purpose of the Study:

• To investigate and compare the pharmacokinetics of tramadol following intravenous (IV) and caudal epidural administration in children.
• To evaluate the systemic absorption and metabolite profiles of tramadol in pediatric surgical patients.

Main Methods:

• A single bolus dose of tramadol (2 mg/kg) was administered intravenously (n=9) or via caudal epidural injection (n=5) to healthy children (1-12 years) undergoing surgery.
• Serum concentrations of tramadol and its metabolite O-demethyl tramadol (MI) were measured up to 20 hours post-administration.
• Pharmacokinetic variables were analyzed using a non-compartmental model and gas chromatography.

Main Results:

• After IV administration, mean elimination half-life was 6.4 h, volume of distribution 3.1 L/kg, and total plasma clearance 6.1 mL/kg/min.
• After caudal epidural administration, mean elimination half-life was 3.7 h, volume of distribution 2.0 L/kg, and total clearance 6.6 mL/kg/min.
• The AUC quotient confirmed extensive systemic absorption of tramadol after caudal epidural administration, with lower MI serum concentrations compared to IV administration.

Conclusions:

• Tramadol exhibits similar pharmacokinetic profiles after IV and caudal epidural administration in children aged 1-12 years.
• Caudal epidural administration leads to extensive systemic absorption of tramadol.
• These findings support the use of caudal epidural tramadol for effective pain management in pediatric surgery.