Summary of
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
interactions.
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results. |
Magnesium*
|
Check: Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details. |
Potassium
Sodium
|
| Depletion or interference |
None known
|
| Side effect reduction/prevention |
None known
|
| Supportive interaction |
None known
|
| Reduced drug
absorption/bioavailability |
None known
|
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
evidence.
Interactions with Dietary Supplements
Folic
acid
One study showed that people taking diuretics for more than six months had dramatically lower
blood levels of folic acid and higher levels of
homocysteine compared with individuals not taking diuretics.1 Homocysteine, a
toxic amino acid byproduct, has been associated with atherosclerosis. Until further information is
available, people taking diuretics for longer than six months should probably supplement with
folic acid.
Magnesium
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.
Potassium
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.
Sodium
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.
References:1. Morrow LE, Grimsley EW. Long-term diuretic therapy in hypertensive
patients: effects on serum homocysteine, vitamin B6, vitamin B12, and red blood cell folate
concentrations. South Med J 1999;92:866–70.
2. Devane J, Ryan MP. The effects of amiloride and triamterene on urinary
magnesium excretion in conscious saline-loaded rats. Br J Pharmacol
1981;72:285–9.
3. Ramsay LE, Hettiarachchi J, Fraser R, Morton JJ. Amiloride,
spironolactone, and potassium chloride in thiazide-treated hypertensive patients. Clin
Pharmacol Ther 1980;27:533–43.