Individualizing theophylline dosage: evaluation of a single-point maintenance dose prediction method

Area of Science:

• Pharmacokinetics
• Clinical Pharmacology
• Respiratory Medicine

Background:

• Theophylline is a crucial medication for managing obstructive airways diseases.
• Accurate theophylline dosing is essential to maximize therapeutic effects and minimize toxicity.
• Predicting individual theophylline clearance and dose requirements can be challenging.

Purpose of the Study:

• To evaluate a dosage prediction method for estimating theophylline clearance and dose requirements.
• To assess the accuracy of a single-point serum theophylline determination for dose prediction.
• To determine the applicability of this method in outpatients with obstructive airways disease.

Main Methods:

• A single oral test dose of theophylline was administered to 22 outpatients.
• Serum theophylline concentration was measured 8 hours post-dose to predict steady-state concentration (Css).
• Theophylline clearance was also assessed in healthy smokers using the area under the curve method for comparison.

Main Results:

• In non-smoking patients, the mean absolute deviation between predicted and observed Css was 8.2%.
• In smoking patients, the mean deviation was significantly higher at 34.0%.
• The single-point method predicted theophylline clearance in healthy smokers with an 11.3% error compared to AUC methods.

Conclusions:

• The single-point theophylline dosage prediction method is effective for non-smoking patients with obstructive airways disease.
• The method shows potential for clinical application within specific elimination rate constant ranges.
• Further refinement may be needed to improve accuracy in patient subgroups, such as smokers.