Hydrochlorothiazide, which became commercially available in 1959, is a medication used to treat swelling that’s caused by heart failure or kidney problems, liver damage, and taking medications called corticosteroids or estrogens. Other uses include diabetes insipidus, renal tubular acidosis, and to decrease the risk of kidney stones in those with a high calcium level in the urine. It is worth noting that this medication acts by decreasing the kidneys' ability to retain water. Plus, Hydrochlorothiazide is taken by mouth, and may also be combined with other blood pressure medications as a single pill to increase effectiveness. Besides, you can take it on an empty stomach or with a meal. As for the potential side effects of this medication, they include poor kidney function, electrolyte imbalances including low blood potassium and less commonly low blood sodium, gout, high blood sugar, and feeling lightheaded with standing. On a side note, women can use Hydrochlorothiazide during pregnancy.