Methods for antihypertensive drug dosing by pharmacokinetic parameter determination. In one embodiment, the antihypertensive drug is olmesartan and the pharmacokinetic parameter is AUC. The methods are effective for treating hypertension. In one aspect, the invention provides a method for olmesartan dosing by AUC. In one embodiment, the method comprises: (a) administering olmesartan at a first dose to a subject in need of hypertension therapy； (b) determining the concentration of olmesartan the subject's blood at one or more time points after administration to provide a set of olmesartan concentration/time data points； (c) transforming the set of olmesartan concentration/time data points to provide area-under-the-curve (AUC)； and (d) administering olmesartan at subsequent doses (e.g., second and subsequent doses) to achieve a target AUC of about 7,000 hr*ng/mL.
