hydrochlorothiazide: a diuretic drug (trade name Microzide, Esidrix, and HydroDIURIL) used in the treatment of hypertension
thiazide: any of a group of drugs commonly used as diuretics in the treatment of hypertension; they block the reabsorption of sodium in the kidneys
professional relation: the relation that exists when one person requests and is granted professional help from a qualified source