An estimated 20 million Americans suffer from diabetes. Patients with non-insulin-dependent diabetes mellitus (NIDDM) comprise approximately 90% of the diabetic population. An estimated 10-30% of patients with NIDDM withdraw from their prescribed regimen within 1 year of diagnosis, and of the remainder, nearly 20% administer insufficient medication to facilitate an adequate reduction in blood glucose. A randomized trial was undertaken to discern the effect of pharmacy-based value-added utilities on prescription-refill compliance with sulfonylurea therapy and health service utilization. The subjects were 258 Medicaid beneficiaries from the state of South Carolina, previously untreated for NIDDM, prescribed 5 mg of the second-generation sulfonylurea glyburide twice daily, and monitored with regard to prescription-refill compliance and health service utilization for 1 year. Subjects provided informed consent and were randomly assigned to one of four experimental groups: (i) the control cohort received standard pharmaceutical care with each dispensing of glyburide; (ii) the second cohort received standard pharmaceutical care and was mailed a medication-refill reminder 10 days prior to each sequential refill date; (iii) the third cohort received standard pharmaceutical care and was provided unit-of-use packaging with each prescription-refill request; (iv) the fourth cohort received standard pharmaceutical care, mailed medication-refill reminders, and unit-of-use packaging. Analysis of variance (ANOVA) procedures revealed that patients receiving mailed prescription-refill reminders, unit-of-use packaging, or a combination of both interventions achieved a significant (P < or = 0.05) increase in the Medication Possession Ratio (MPR) for sulfonylurea therapy relative to controls.(ABSTRACT TRUNCATED AT 250 WORDS)