Accuracy of 11 methods for predicting theophylline dose.

Area of Science:

• Pharmacokinetics
• Clinical Pharmacology
• Asthma Management

Background:

• Theophylline is a critical medication for managing asthma, requiring precise dosing to maintain therapeutic serum concentrations.
• Accurate pharmacokinetic determination of theophylline dosage is essential to optimize efficacy and minimize toxicity.

Purpose of the Study:

• To compare the predictive accuracy of eleven distinct methods for determining theophylline dosage in adult asthma patients.
• To evaluate the performance of various Bayesian and non-Bayesian approaches in predicting theophylline serum concentrations and clearance.

Main Methods:

• Eleven pharmacokinetic methods were assessed, including variations of the Chiou method, seven Bayesian approaches, FDA's standardized clearance estimate, and a population-based method.
• Predictions were compared against actual serum theophylline concentrations in 22 adult asthma patients receiving loading and maintenance doses.
• A one-compartment, open model with first-order elimination was assumed for all calculations.

Main Results:

• All eleven methods exhibited minimal bias and good precision in predicting steady-state theophylline concentrations.
• Bayesian methods, particularly those using four measured concentrations, showed high precision. The population-based method demonstrated the highest correlation coefficient and lowest mean error.
• Reducing the number of measured concentrations had a negligible impact on the Bayesian methods' accuracy.

Conclusions:

• All evaluated theophylline dosing methods are sufficiently accurate for clinical application in patients with stable, uncomplicated asthma.
• Bayesian and population-based methods offer high precision for pharmacokinetic determination of theophylline dosage.
• The choice of method may depend on clinical setting and available patient data, but all tested approaches are viable.