 [ Symptoms ] i have perimenapause can u get pregnant i took test and two lines appeared what to do [ Disease ] you ask a great question many popular diuretics aka water pills used to manage heart disease usually high blood pressure have a specific side effect they reduce potassium levels in the blood this is important because potassium helps regulate your heart rhythm low potassium levels can cause an irregular heartbeat or even a heart attack this is why people who take hydrochlorothyazide hctz are given a potassium supplement taking the supplement helps keep potassium levels normal in the bloodstream if someone has been given hctz and was not told to take a potassium supplement you should call the cardiologist or other medical professional to find out why if the person was told to take a potassium supplement with their hctz and they are not doing it you should let them know they could be endangering their health if you have any questions contact your or the person is heart doctor for more information about hctz and potassium wishing you well