One study showed that people taking diuretics for more than six months had dramatically lower blood levels of folic acid and higher levels of Reference homocysteine compared with individuals not taking diuretics.¹ Homocysteine, a toxic amino acid byproduct, has been associated with Reference atherosclerosis. Until further information is available, people taking diuretics for longer than six months should probably supplement with folic acid.

Preliminary research in animals suggests that amiloride may reduce the urinary excretion of magnesium.² It is unknown if this same effect would occur in humans. Nevertheless, persons taking more than 300 mg of magnesium per day and amiloride should consult with a doctor, as this combination may lead to potentially dangerous elevations in levels of magnesium in the body. The combination of amiloride and hydrochlorothiazide would likely eliminate this problem, as hydrochlorothiazide may deplete magnesium.

As a potassium-sparing drug, amiloride reduces urinary loss of potassium.³ This can cause potassium levels to build up in the body. People taking this drug should avoid use of potassium chloride–containing products, such as Morton Salt Substitute, No Salt, Lite Salt, and others. Even eating several pieces of fruit per day can sometimes cause problems for people taking potassium-sparing diuretics, due to the high potassium content of fruit.

However, one medication (Moduretic) contains the combination of the potassium-sparing drug amiloride and the potassium-depleting drug hydrochlorothiazide. With the use of Moduretic, potassium excess and potassium depletion are both possible. People taking this combination drug should have their potassium levels monitored by a doctor to determine whether their potassium intake should be increased, reduced, or kept the same.

Diuretics, including amiloride, cause increased loss of sodium in urine. By removing sodium from the body, diuretics cause water to leave the body as well. This reduction of water in the body is the purpose of taking amiloride. Therefore, there is usually no reason to replace lost sodium, although strict limitation of salt intake in combination with the action of diuretics can sometimes cause excessive sodium depletion. On the other hand, people who restrict sodium intake and in the process reduce blood pressure may need to have the dose of their diuretics lowered.