In our casuistic, we treated hypertensive AD patients with Enalapril (10–20 mg/day) for one month and performed a pharmacogenetic study assessing the potential influence of APOE, NOS3, ACE, AGT, and CYP2D6, 2C19, 2C9, and 3A4/5 variants on blood pressure response to this competitive inhibitor of the angiotensin-converting enzyme. The gene discussed is CYP2D6; the disease is Alzheimer disease.