- Hypertension is considered resistant if blood pressure cannot be reduced to <140/90 mmHg with an appropriate triple-drug regimen, including an oral diuretic, with all agents administered at maximal dosages. This definition has evolved with the development of new therapies and evidence-based data supporting treatment to lower BP goals. To assess whether vitamin C and atorvastatin improve endothelial function and blood pressure control in subjects with resistant arterial hypertension and dyslipidemia. Forty-eight hyperlipidemic subjects with RH (office systolic BP >140 mmHg and/or office diastolic BP >90 mmHg notwithstanding antihypertensive treatment with three medications in maximal doses) were randomized into three groups to receive additional medication for 8 weeks. Group VTC (n = 17)--mean 24 hour SBP 150.6 +/- 5.2 mmHg, DBP 86.1 +/- 3.3 mmHg, low density lipoprotein 158.1 +/- 24.5 mg/dl--received vitamin C 500 mg per day; Group ATR (n = 15)--mean 24 hour SBP 153.1 +/- 4.8 mmHg, DBP 87.1 +/- 6.7 mmHg, LDL 162.6 +/- 13.6 mg/dl--received atorvastatin 20 mg/day; and Group PLA (n = 16)--mean 24 hour SBP 151.1 +/- 7.4 mmHg, DBP 84.8 +/- 5.9 mmHg, LDL 156.7 +/- 26.1 mg/dl--received a placebo. High resolution ultrasound was used to calculate brachial artery flow-mediated dilation, and 24 hour ambulatory BP monitoring was performed at study entry and after 8 weeks. In the ATR group there were significant reductions of SBP (deltaSBP1-2: 13.7 +/- 5.6 mmHg, P 0.001), DBP (deltaDBP1-2: 7.8 +/- 5.7 mmHg, P 0.01), LDL (deltaLDL1-2: 67.7 +/- 28.3 mg/dl, P < 0.001) and improvement of brachial artery FMD (deltaFMD2-1: 4.2 +/- 2.6%). No significant changes in BP, LDL and FMD were observed in the other two groups. In subjects with RH and dyslipidemia, atorvastatin 20 mg/day compared to vitamin C 500 mg/day may help to achieve better BP control and improve endothelial function in a finite period. A larger trial is needed to assess the drug's efficacy in this population for longer periods.