Children are increasingly being diagnosed with essential hypertension and the absence of comparative effectiveness research in antihypertensive therapies has contributed to considerable differences in prescribing practices among physicians treating children with essential hypertension.

This study will consist of a series of systematically-administered n-of-1 trials among children to verify the need for ongoing antihypertensive treatment and if so, to identify the preferred single drug therapy.

This is a series of systematically-administered n-of-1 trials among children with essential hypertension to verify the need for ongoing antihypertensive treatment and if so, to identify the preferred single drug therapy from among the three major classes of drugs commonly used for essential hypertension (angiotensin converting enzyme inhibitors, calcium channel blockers, and diuretics). The investigators will determine whether there is one that is preferred for the great majority of patients. The "preferred" therapy will be defined as the drug which produces normal ambulatory blood pressure, with the greatest reduction in awake mean systolic blood pressure without unacceptable side effects.

For each patient, the order of the 3 drugs will be assigned randomly and each drug will be taken for 2 weeks. The effectiveness of each drug will be measured with 24-hour ambulatory blood pressure monitoring, and tolerability will be assessed using a side effect questionnaire. Participants will rotate through treatment periods, repeating drugs and adjusting doses until the preferred therapy is identified. In assessing whether one the medications is most effective for the great majority of subjects, the primary outcome will be the percentage of participants for whom each drug is selected as the preferred therapy. Primary hypothesis: no drug will be selected for the majority of the subjects, a finding that would support consideration of clinical use of n-of-1 trials. Secondary analyses will explore whether patient characteristics predict which medication will be selected as a preferred drug.

Inclusion Criteria:

• Clinical diagnosis of essential hypertension
• Treating physician has determined that pharmacologic therapy is necessary

Exclusion Criteria:

• Compelling indication to select one particular medication
• Specific contraindication for any of the 3 therapies

All subjects who participated in an n-of-1 trial received all three interventions in a cross-over fashion.

2 weeks