Irregular drug intake and serum chlorpropaminde concentrations.

In patients with maturity onset diabetes serum chlorpropamide concentrations (s-CPA) and fasting blood glucose (FBG) were measured before and after self recording of drug intake in order to evaluate the role of compliance with the therapeutic regimen in variation in s-CPA and clinical outcome. Nine out of 57 patients (16%) had to be excluded because they did not comply with the clinical routines and the test procedure. Of the remaining 48 patients, only two recorded small deviations from the prescribed dosage, and nine (19%) noted variations in medication time of more than +/- 2h. By contrast, irregular drug intake was indicated in 29 of the 48 patients (60%) based on statistical evaluation of changes in s-CPA. Clinical control (FBG) was influenced significantly in only half of these 29 patients. Improved adherence to the dietary regimen was observed in 12 of the 48 patients (25%). Patient medication behaviour seems to be an important determination of variation in s-CPA, and is as important as adherence to the dietary regimen in clinical control of "drug requiring" patients with maturity onset diabetes.