Why measure plasma theophylline concentrations

Summary

Studies have been carried out with a number of theophylline preparations, both in normal subjects and inpatients with obstructive airways disease, to obtain information about plasma theophylline concentrations. With some of the formulations studied, ‘usual’ or recommended doses failed to produce plasma theophylline levels within the optimum range of 10 to 20 μg/ml. Because of the large inter-individual variation between patients, it would appear that dose requirements with different drugs should be carefully monitored and that regular plasma theophylline concentration measurements should be considered in patients with obstructive airways disease, particularly when clinical management is difficult.

Key Words::

• Theophylline
• biological availability
• dosage forms
• lung diseases
• obstructive