OBJECTIVES: Determine the association between antihypertensive medication class and blood pressure(BP) control and determine persistence of subjects on monotherapy for hypertension in veterans. METHODS: Blood pressure (BP) measurements and pharmacy records were obtained from Southern Arizona Veterans Affairs Healthcare System. Variables of interest included demographics, BP measurements, and pharmacy dispensings. Medications classified by VA class codes included ten distinct subclasses. Mean systolic BP(SBP) and diastolic BPs(DBP) were categorized according to JNC-7 classifications. Association of BP control using mean SBP and antihypertensive class was determined. Medication persistence was calculated. Cox proportional hazards analysis was performed to examine the hazard ratio(HR) of discontinuation of medication class. RESULTS: A total of 16,195 veterans obtained 49,254 antihypertensive medication dispensings from August 12, 2002 to February 2, 2004. Of these, 4787 received monotherapy. For persons on monotherapy, mean(SD) age was 64.9+12.8 years; 93.4% were male. A total of 346 had normal SBP, but 4441 subjects had high SBP. Mean SBP control was significantly different between antihypertensive classes(X2 = 7.9e+3, p <0.001). Use of beta-blockers and ACE-inhibitors were more likely to be associated with subjects who had controlled blood pressure, 47.1% and 23.1% respectively. Among subjects with high SBP, beta-blockers and ACE-inhibitors were used in 34.5% and 30.9% of subjects. The likelihood of discontinuing therapy was statistically significantly lower among subjects receiving angiotensin receptor blockers(ARB), (HR 0.31, 95%CI 0.1-0.9). CONCLUSION: Among veterans taking antihypertensive monotherapy, subjects on beta-blockers were more likely to have controlled BP compared to other antihypertensive medication classes. This could be due to high prescribing rates, not necessarily success or failure as monotherapy. Side effects/preference may lead to different persistence rates between classes, but persons on ARBs were less likely to discontinue therapy. These results should be viewed cautiously since the analysis may have been influenced by unmeasured patient characteristics and formulary considerations.