Effect of type II diabetes mellitus on theophylline elimination

Theophylline elimination was studied in poorly-controlled and well-controlled type II diabetic patients, seven in each group. Eight healthy volunteers served as a control group. After a single oral dose of theophylline (200 mg) the drug concentration was measured in plasma, collected at different time intervals, using a high pressure liquid chromatography method. The poorly-controlled diabetics had significantly longer elimination half-life (t1/2) due to increased apparent volume of distribution (V) of the drug when compared to well-controlled diabetics. Their clearance rate (Cl) remained unaltered. There was no significant difference in these parameters between healthy volunteers and diabetic patients, although poorly-controlled diabetics had a tendency for higher t1/2 and V. It is concluded that theophylline clearance is unaltered in type II diabetic patients.