AmlodipineCalcium Channel BlockersAntihypertensive AgentsDihydropyridinesTetrazolesHydrochlorothiazideAzetidinecarboxylic AcidHypertensionValineBlood PressureChlorthalidoneNifedipineLisinoprilDrug Therapy, CombinationAngiotensin II Type 1 Receptor BlockersMibefradilDouble-Blind MethodAtenololBenzimidazolesAngiotensin-Converting Enzyme InhibitorsCross-Over Studies