 Resistant hypertension RH is characterized when the blood pressure BP remains above the recommended goal after taking three antihypertensive drugs with synergistic actions, at their maximum recommended tolerated doses for at least six months; one preferably should be a diuretic. True RH should be differentiated from pseudo resistance, which occurs due to non-adherence to treatment, inadequate BP measurements, inadequate doses of medications, inappropriate therapeutic regimens, or the presence of the so-called white-coat effect. 