OBJECTIVES: Using longitudinal data, this study examined the determinants of pharmaceutical expenditures for patients with hypertension, and the impact of lifestyle and marriage status changes on pharmaceutical expenditures. METHODS: The longitudinal household components and the prescribed medicine data of Medical Expenditure Panel Survey (MEPS) for year 2008 and 2009 were employed. Five rounds of the survey were conducted for Panel 13 households between years 2008 and 2009. Only round 3 and round 5 surveys were used for this work because BMI values were only included in these two rounds. I included individuals older than 18 years, not pregnant, with hypertension but no other comorbid conditions, and who had obtained a prescription for antihypertensive agents for essential hypertension (ICD-9 code 401). The final panel data contained 1814 observations, among which average age was 53.65 years (SD=13.49), the average age at the time of hypertension diagnosis was 44.22 (SD=13.43) years, 49.91% (SD=0.50) were male. Ordinary Least Square and Mixed Effect Model were employed to investigate the determinants of pharmaceutical expenditure for patients with hypertension. RESULTS: Pharmaceutical expenditures increased with age and the duration of hypertension. A mixed effect model indicated that being widowed or separated significantly increased pharmaceutical expenditures by $219.12 (P<0.0001) and $206.84 (P<0.0001) respectively; the pharmaceutical expenditures decreases by $2.79 (P<0.01) if BMI decreased by 1 kg/m2 from survey round 3 to round 5. Pharmaceutical expenditures decreased with family size and education level. Compared with the uninsured, those with public insurance spent $208.33 (P<0.0001) more, and those with private insurance spent $121.01 (P<0.0001)more on prescribed medicine for essential hypertension. CONCLUSIONS: Age, duration of hypertension, marriage status, BMI, type of insurance, and education were found as significant determinants of pharmaceutical expenditures for patients with hypertension.