Resistant hypertension.

Resistant hypertension is most often due to insufficient medical therapy. With a patient history, physical examination and focused laboratory tests, sufficient information can be gathered to lead to further directed medical therapy, which most often includes a diuretic as part of the drug regimen. Patients may require four or more classes of antihypertensives, some at high doses to achieve control. The clinician must be prepared to use sufficient medications at sufficient doses to achieve blood pressure targets. Referral to a hypertension specialist is appropriate if blood pressure remains uncontrolled despite therapy with three antihypertensive medications.