The use of diuretics in children is typically seen for the treatment of milder degrees of heart failure. There is no indication that the risk of side effects from diuretics is different in children than in adults. Dosages are lower for children and the dosage interval may be longer. Children taking potassium-sparing diuretics are more prone to developing calcium deficiencies than are adults. Safety of diuretic use in children has not been scientifically established for all forms of the medication. Parents are encouraged to discuss the potential risks and benefits with a board-certified pediatric cardiologist before their child begins taking diuretics. 

Older adults have a higher frequency and intensity of side effects, such as lightheadedness, dizziness and fainting (syncope). They are also more susceptible to dehydration, hypovolemia (decrease in circulating blood volume), and deficiencies of calcium, potassium, sodium and magnesium. Generally, older patients require lower doses of diuretics and require close observation but are routinely prescribed these medications.