Hypertension and Chronic Kidney Disease: Cause and Consequence – Therapeutic Considerations 45 Elsa Morgado and Pedro Leão Neves Potassium-Sparing Diuretics in Hypertension 67 Cristiana Catena, GianLuca Colussi and Leonardo A. Sechi Hypertension and Renin-Angiotensin System Roberto de Barros Silva Pharmacokinetic Interactions of Antihypertensive Drugs with Citrus Juices 95 Yoshihiro Uesawa Drug Interaction