Plasma theophylline levels after sustained-release aminophylline

Area of Science:

• Pharmacokinetics
• Clinical Pharmacology
• Drug Formulation

Background:

• Aminophylline is a common bronchodilator.
• Understanding sustained-release (SR) formulations is crucial for effective therapeutic drug monitoring.
• Individual variability in drug metabolism necessitates personalized dosing strategies.

Purpose of the Study:

• To evaluate the pharmacokinetic profile and therapeutic efficacy of a sustained-release aminophylline formulation.
• To determine the range of doses required for adequate plasma theophylline levels.
• To assess the safety and tolerability of different SR aminophylline doses.

Main Methods:

• Healthy adults received oral SR aminophylline (225 mg or 450 mg 12-hourly) for 5 doses.
• Intravenous aminophylline (225 mg) was administered to determine individual kinetic parameters.
• Plasma theophylline levels were measured over 12 hours post-dose.
• Adverse events were recorded and analyzed.

Main Results:

• Mean theophylline half-life was 5.8 hours.
• Plasma theophylline levels varied significantly between the 225 mg and 450 mg SR doses.
• Higher doses (450 mg) were associated with increased incidence of side effects including headache, nausea, insomnia, and anxiety.

Conclusions:

• A wide range of doses is necessary to achieve adequate plasma theophylline concentrations.
• The studied SR aminophylline formulation can provide stable levels once individualized.
• Dose optimization is critical to balance efficacy and tolerability.