OBJECTIVES: To assess type, duration, and medication availability of antihypertensive therapy among veterans. METHODS: Electronic medical records from the Central Texas Veterans Health Care System were extracted for adults newly diagnosed with hypertension between 1995 and 2003. Information on demographic (age, gender, and race/ethnicity) and clinical (diagnoses, height, weight, labs, and blood pressure values) characteristics were collected. Drug utilization was measured as a time-dependent variable; thus, the use of combination therapies was captured for any given day for each patient in the sample. Medication availability was calculated as the ratio of ‘total days supply' and ‘number of days between first and last refill.' RESULTS: The average age of the participants (N=11,187) was 60.7 (SD: 12.7). Half (50.1%) of the patients could be categorized as having controlled blood pressure. Veterans were followed for an average of 3.6 years (total of 51,549 person-years). Overall, 29,561 treatment episodes were identified; an average of about 2.6 per patient. Over forty percent (41.6%) of these episodes involved one medication only, but patients frequently used dual (26.9%) and three or more (15.9%) combination therapies. Patients took ‘single therapy alone' for a median of 1.3 years, ‘dual therapies alone' for a median of 1.0 years, whereas ‘three or more therapies' for a median of 0.9 years. Medication availability ratios were relatively high, ranging from 0.88 to 0.93. Overall, calcium channel blockers (22.4%), angiotensin converting enzyme inhibitors (21.4%), and beta-blockers (19.9%) were used most frequently. CONCLUSIONS: Our results indicate high medication availability ratios; i.e., veterans filled their antihypertensive medications as it was prescribed by their physicians. Nevertheless, the average blood pressure control rate was only 50 percent, which requires improvements in patients' antihypertensive therapy. The necessity of better selection of antihypertensive therapies is also supported by the finding of frequent therapy changes.