Hydrochlorothiazide may increase blood glucose levels. As a thiazide diuretic. Hydrochlorothiazide reduces the swelling and water retention caused by various medical conditions, such as heart, liver, or kidney disease. Microzide is used for the treatment of edema, and for high blood pressure. Hydrochlorothiazide from the gut. If you are also taking Hydrochlorothiazide along with diazoxide or a beta-blocker medicine. Some of the side effects that may occur while taking Microzide include black, tarry stools blood in urine or stools cough or hoarseness fever or chills joint pain lower back or side pain painful or difficult urination. Hydrochlorothiazide has an additive effect on lowering blood pressure.