Loop diuretics constitute a family of drugs that remove water from the body. They are
referred to as potassium-depleting, as they cause the body to lose potassium as well as water.
Potassium-depleting diuretics also cause the body to lose magnesium. Loop diuretics are more
potent than thiazide diuretics. They are used
to lower blood pressure in people with
hypertension and to reduce the amount of work the heart has to do, allowing it to pump
better in people with congestive heart
failure. Loop diuretics are also used to reduce water accumulation caused by other diseases.
Helpful Products
Try these helpful products which may be beneficial if taken with this medicine
Potassium
To avoid depleting potassium, which can lead to muscle cramps, twitches, and an irregular
heartbeat, take a potassium supplement and eat more fruits (especially bananas), vegetables,
and juices
Magnesium
To avoid depleting magnesium, which can lead to weakness, muscle tremors, twitches, and
mental dullness, supplement with 300 to 600 mg per day, or eat more nuts, grains, and
beans
Folic acid
Preliminary research suggests that furosemide might deplete this nutrient, so
supplementing with 400 mcg per day may help improve blood levels
These recommendations are not comprehensive and are not intended to
replace the advice of your doctor or pharmacist. Continue reading the full article for more
information on interactions with vitamins, herbs, and foods.
The information in this article pertains to loop diuretics in general. The interactions
reported here may not apply to all the Also Indexed As terms. Talk to your doctor or
pharmacist if you are taking any of these drugs.
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.
May Be Beneficial:Depletion or
interference—The medication may deplete or interfere with the absorption or
function of the nutrient. Taking these nutrients may help replenish them.
Folic acid*
Magnesium
Potassium
Vitamin B1
Avoid:Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results.
Alder Buckthorn*
Buchu
Buckthorn*
Cleavers
Dandelion
Digitalis
Gravel root
Horsetail
Juniper
Licorice
Uva ursi
Check:Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details.
Sodium
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 and Potassium
Potassium-depleting diuretics, including loop diuretics, cause the body to lose potassium.
Loop diuretics may also cause cellular magnesium depletion,2 although this
deficiency may not be reflected by a low blood level of magnesium.3 Magnesium loss
induced by potassium-depleting diuretics can cause additional potassium loss. Until more is
known, it has been suggested that people taking potassium-depleting diuretics, including loop
diuretics, should supplement both potassium and magnesium.4
People taking loop diuretics should be monitored by their doctor, who will prescribe
potassium supplements if needed. Such supplementation is particularly critical before surgery
in patients with a history of heart disease. In a preliminary study, people with low blood
levels of potassium (in part related to diuretic use) had a higher incidence of serious
problems resulting from surgery (including death) compared with those having normal potassium
levels.5 Fruit is high in potassium, and increasing fruit intake is another way of
supplementing potassium. Magnesium supplementation is typically 300–400 mg per day.
Vitamin
B1
People with congestive heart failure (CHF)
treated with the loop diuretic furosemide may be at risk for vitamin B1 deficiency due to: 1)
the disease, 2) treatment with furosemide, and/or 3) inadequate dietary vitamin B1
intake.6 In a study of people with CHF, long-term furosemide therapy was associated
with clinically significant vitamin B1 deficiency due to urinary losses.7 This
furosemide-induced vitamin B1 deficiency may worsen heart function in patients with CHF and
may be prevented or corrected with vitamin B1 supplementation.8
Sodium
Diuretics, including loop diuretics, cause increased loss of sodium in the urine. By removing
sodium from the body, diuretics also cause water to leave the body. This reduction of body
water is the purpose of taking diuretics. Therefore, there is usually no reason to replace
lost sodium, although strict limitation of salt intake in combination with the actions 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 their dose of diuretics lowered.
Interactions with Herbs
Herbs that have a diuretic effect should be avoided when taking diuretic medications, as
they may enhance the effect of these drugs and lead to possible cardiovascular side effects.
These herbs include dandelion, uva ursi,
juniper, buchu, cleavers,
horsetail, and gravel root.9
Alder Buckthorn,
Buckthorn(Rhamnus catartica, Rhamnus
frangula, Frangula alnus)
Use buckthorn or alder buckthorn for more than ten days consecutively may cause a loss of
electrolytes (especially the mineral potassium). Medications that also cause potassium loss,
such as some diuretics, should be used with caution when taking buckthorn or alder
buckthorn.10
Digitalis (Digitalis purpurea)
Digitalis refers to a family of plants commonly called foxglove that contain digitalis
glycosides, chemicals with actions and toxicities similar to the prescription drug digoxin. Loop diuretics can increase the risk of
digitalis-induced heart disturbances.11 Loop diuretics and digitalis-containing
products should only be used under the direct supervision of a doctor trained in their
use.
Licorice(Glycyrrhiza glabra)
Licorice may enhance the side effects of potassium-depleting diuretics, including loop
diuretics.12 Loop diuretics and licorice should be used together only under careful
medical supervision. Deglycyrrhizinated licorice (DGL) may be used safely with all
diuretics.
Interactions with Foods and Other Compounds
Food
Furosemide (Lasix®) is most effective taken on an empty stomach, one hour before
eating.13 However, furosemide may be taken with food to prevent gastrointestinal
(GI) upset.14 Torsemide (Demadex®) may be taken with or without
food.15
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
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. Martin B, Milligan K. Diuretic-associated hypomagnesiumia in the
elderly. Arch Intern Med 1987;147:1768–71.
3. Kroenke K, Wood DR, Hanley JF. The value of serum magnesium
determination in hypertensive patients receiving diuretics. Arch Intern Med
1987;147:1553–6.
4. Whang R, Whang DD, Ryan MP. Refractory potassium repletion—a
consequence of magnesium deficiency. Arch Intern Med 1992;152:40–5.
5. Wahr JA, Parks R, Boisvert D, et al. Preoperative serum potassium
levels and perioperative outcomes in cardiac surgery patients. JAMA
1999;281:2203–10.
6. Brady JA, Rock CL, Horneffer MR. Thiamin status, diuretic medications,
and the management of congestive heart failure. J Am Dietet Assoc
1995;95:541–4.
7. Seligman H, Halkin H, Rauchfleisch S, et al. Thiamine deficiency in
patients with congestive heart failure receiving long-term furosemide therapy: A pilot study.
Am J Med 1991;91:151–5.
8. Shimon I, Almog S, Vered Z, et al. Improved left ventricular function
after thiamine supplementation in patients with congestive heart failure receiving long-term
furosemide therapy. Am J Med 1995;98:485–90.
9. Brinker F. Herb Contraindications and Drug Interactions.
Sandy, OR: Eclectic Institute, 1997, 102–3.
10. European Scientific Cooperative on Phytotherapy (ESCOP). Frangulae
cortex, frangula bark. Monographs on the Medicinal Uses of Plant Drugs. Exeter, UK:
University of Exeter, Centre for Complementary Health Studies, 1997.
11. Threlkeld DS, ed. Diuretics and Cardiovasculars, Thiazides and
Related Diuretics. In Facts and Comparisons Drug Information. St. Louis, MO: Facts
and Comparisons Drug Information, Apr 1993, 135a–7c.
12. Shintani S, Murase H, Tsukagoshi H, Shiigai T. Glycyrrhizin
(licorice)-induced hypokalemic myopathy. Report of two cases and review of the literature.
Eur Neurol 1992;32:44–51.
13. Threlkeld DS, ed. Diuretics and Cardiovasculars, Loop Diuretics. In
Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr
1994, 137d–8.
14. Threlkeld DS, ed. Diuretics and Cardiovasculars, Loop Diuretics. In
Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr
1994, 137d–8.
15. Threlkeld DS, ed. Diuretics and Cardiovasculars, Loop Diuretics. In
Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr
1994, 137d–8.
The information presented in Healthnotes is for informational purposes
only. It is based on scientific studies (human, animal, or in vitro), clinical
experience, or traditional usage as cited in each article. The results reported may not
necessarily occur in all individuals. For many of the conditions discussed, treatment with
prescription or over the counter medication is also available. Consult your doctor,
practitioner, and/or pharmacist for any health problem and before using any supplements or
before making any changes in prescribed medications. Information expires June 2009.
