[How I investigate...a refractory hypertension].

Hypertension is a cardiovascular risk factor which needs a good evaluation before treatment. When this latter is decided, the target is to normalize high blood pressure. This requires a complete information of the patient; the latter will also receive individualized non pharmacological advices and, also, possibly different antihypertensive drugs. When blood pressure does not normalize, one must check the blood pressure measurement technique, the compliance to treatment and potential pharmacologic interferences. Secondary hypertension is only considered if resistance to therapy cannot be found. It should be remembered that obesity and sleep apnea disorders are responsible of many instances of refractory hypertension.