When first taking a diuretic, patients should avoid operating heavy machinery (e.g., driving) until they know how the medication will affect them. Some patients may experience fatigue when first taking this medication, but this usually passes after the patient has been on the medication for some time. Urine flow will increase and some patients may need to wake during the night to urinate. To minimize this, patients with a single daily dose should take their medication in the morning after breakfast. Patients taking more than one dose a day are advised to take their last dose before 6 p.m. In addition, some diuretics can increase the skin’s sensitivity to sunlight. Patients are advised to use sunscreen and avoid tanning booths. Furthermore, patients being treated for heart failure may need to weigh themselves frequently and report any loss or gain of more than 5 pounds in a week.

Patients should drink enough liquids during exercise or in hot weather and follow their physician’s instructions regarding exercise, activity levels and diet. Physicians may instruct patients to add foods high in potassium to their diets or prescribe a potassium supplement, but patients should not attempt to change their diets without direction from their physician. Extra potassium is not necessary for every patient on diuretics and too much potassium can be harmful. In addition, patients taking loop diuretics may be advised to take magnesium supplements in addition to potassium supplements, because the reabsorption of this solute is limited by the medication.

Most patients taking diuretics to treat high blood pressure (hypertension) will be using the medication for the rest of their lives, provided no serious side effects occur. Patients should remember that diuretics can help to control high blood pressure, but cannot cure it. Even if all their symptoms cease, patients should continue to take their medication exactly as directed and to keep all scheduled follow-up appointments with their physician.