Methyldopa/HCTZ is part of the Alpha-2 Agonist / Thiazide Diuretic Combinations class and treats Hypertension. Alpha-2 agonist / thiazide diuretic combinations are used to lower blood pressure to treat hypertension. They work by relaxing blood vessels and removing excess water and salt from the body. Methyldopa/HCTZ is only available as a generic drug.