ABSTRACT
<p><b>OBJECTIVE</b>To investigate the impact of antihypertensive medication timing on degree and stability of blood pressure (BP) lowering in patients with moderate and severe essential hypertension.</p><p><b>METHODS</b>Ninety patients were randomly assigned to take Valsartan and Felodiping together in the morning (group A), Valsartan in the morning and Felodiping in the evening (group B) or Felodiping in the morning and Valsartan in the evening (group C, n = 30 each). The morning dosage was titrated if the goal blood pressure was not achieved. Ambulatory blood pressure monitoring (ABPM) was performed on the first and 14(th) day of medication.</p><p><b>RESULTS</b>The BP reductions during nighttime and twenty-four in group B and C hours were similar (P > 0.05) but were significant more than those in group A (P < 0.05). The smoothness indexes of mean systolic, mean arterial blood pressure during nighttime and twenty-four in group B and C were similar but significantly higher than that in group A (P < 0.05). The smoothness index of diastolic pressure at nighttime in group B and C was similar but significantly higher than that in group A (P < 0.05).</p><p><b>CONCLUSION</b>More significant and stable antihypertensive effects could be achieved by taking the two antihypertensive medications separately in the morning and at evening compared that taken the two drugs together in the morning.</p>