Diuretics: Uses, common brands, and safety info

Diuretics, commonly known as “water pills,” increase the amount of fluid expelled from the body through urine. One of the most well-known, natural diuretics is caffeine, often found in coffee and tea. However, caffeine has mild diuretic effects and is not typically used as a diuretic in medical settings. 

The modern history of diuretics started in 1919 when a medical student found that injections containing mercury were effective for excreting water in syphilis patients. It wasn’t until the 1950s and 1960s that commonly prescribed thiazides and loop diuretics were discovered and widely used. Today, diuretics are typically prescribed to treat high blood pressure and other conditions.  

Continue reading to learn more about the different types of diuretics, their uses, and side effects.

Other diuretics

• Naturetin (bendroflumethiazide)

• Enduron (methyclothiazide)

• Renese (polythiazide)

• Saluron (hydroflumethiazide)

• Diamox (acetazolamide)

• Daranide (dichlorphenamide)

• Neptazane (methazolamide)

• Osmitrol (mannitol)

What are diuretics?

Otherwise known as “water pills,” diuretics are medications that increase the amount of salt and water excreted from the body. These medications increase the production of urine produced in the kidneys, which leads to increased urine flow, or diuresis. Diuretics are typically used to treat high blood pressure (hypertension) and fluid retention, or edema, that develops as a symptom of heart failure, kidney problems, and liver failure. Some diuretics can also be used to treat swelling in the brain caused by a severe head injury or swelling in the eyes caused by eye conditions like glaucoma. 

How do diuretics work?

Diuretics work by altering the balance of water, salt, and electrolytes in the body. 

More specifically, they have effects on the different processes in the kidneys that play a role in sodium and electrolyte reabsorption. There are several different types of diuretics. Each of them may work in different parts of the kidney, the filtering organ of the body. Due to the increased concentration of sodium released from the kidneys, more water is drawn out of the body in the urine.

It may be important to understand the structure of the kidney and how it works to completely understand how diuretics work. Each kidney contains over 1 million nephrons, which are the filtration units that remove wastes and produce urine in the body. Depending on the type of diuretic, these medications typically work in the proximal convoluted tubule, the ascending limb of the loop of Henle, the distal convoluted tubule, or the collecting tubule. 

What are diuretics used for?

Diuretics can be used to treat a variety of different conditions that affect the heart, kidneys, and liver. They are also used as antihypertensives to lower blood pressure. Diuretics are sometimes abused by those with eating disorders in order to lose weight. Diuretics can only be obtained with a prescription and may be used to treat the following:

• Heart failure

• Left ventricular failure

• High blood pressure

• Acute renal failure

• Oliguric renal failure

• Kidney stones

• Acute kidney injury

• Kidney disease

• Liver disease

• Pulmonary edema

• High levels of blood calcium (hypercalcemia)

• High levels of blood potassium (hyperkalemia)

• Nephrogenic diabetes insipidus

• High intracranial pressure 

• Glaucoma

Types of diuretics

Thiazide diuretics

Thiazides target the sodium-chloride cotransporter to block the reabsorption of sodium, which helps regulate sodium and blood pressure levels. As a class of drugs, thiazide diuretics block the reabsorption of approximately 5% of sodium in the distal convoluted tubule. Thiazides also block the reabsorption of potassium, which can lead to excess elimination of potassium from the body. Low potassium levels (hypokalemia) can lead to abnormal heart rhythms, among other problems. Because of their effects, thiazides are often used as a first-line treatment for hypertension instead of ACE inhibitors. Examples of thiazides include Microzide (hydrochlorothiazide) and Hygroton (chlorthalidone). 

Loop diuretics

Like thiazides, loop diuretics also help regulate sodium levels in the kidney. However, loop diuretics work in the ascending limb of the loop of Henle in the nephron. These medications target the sodium-potassium-chloride cotransporter to block sodium and water reabsorption. Loop diuretics can also decrease potassium absorption, which can lead to low potassium levels in the body. Loop diuretics can be used to treat heart failure, kidney failure, high potassium levels (hyperkalemia), high calcium levels (hypercalcemia), and most types of edema, such as pulmonary edema. Examples of loop diuretics include Bumex (bumetanide) and Lasix (furosemide), as well as Demadex (torsemide). 

Potassium-sparing diuretics 

Potassium-sparing diuretics do not cause increased secretion of potassium into the urine. Potassium-sparing diuretics like amiloride bind to sodium channels to decrease the reabsorption of sodium into the blood. This increases fluid loss without decreasing potassium levels. Other potassium-sparing diuretics like spironolactone work in the distal tubule and collecting ducts to block the effects of aldosterone, a steroid hormone that increases sodium reabsorption. Examples of potassium-sparing diuretics include Midamor (amiloride), Dyrenium (triamterene), Aldactone (spironolactone), and Inspra (eplerenone). 

Carbonic anhydrase inhibitors

Carbonic anhydrase is an enzyme found in different parts of the body, including the red blood cells and the proximal convoluted tubule of the kidney. This enzyme helps the body reabsorb sodium, bicarbonate, and chloride. Carbonic anhydrase inhibitors block this enzyme to excrete these substances and excess water from the body. Carbonic anhydrase inhibitors are often used to treat glaucoma. Examples include Diamox (acetazolamide) and Neptazane (methazolamide). 

Other diuretics

Xanthine diuretics are a type of mild diuretic that blocks the reabsorption of fluid in the proximal tubule of the kidney. Examples of xanthine diuretics include caffeine and Diurex (pamabrom). Osmotic diuretics use the process of osmosis to draw off fluid and decrease fluid retention. Osmotic diuretics primarily work in the proximal tubule and the loop of Henle. A commonly used osmotic diuretic is Osmitrol (mannitol), which is used to reduce intracranial pressure and treat acute renal failure. 

Who can take diuretics?

Adults

Diuretics are commonly used to treat edema and other cardiovascular conditions in adults. The use of diuretics in adults will depend on the treated condition. 

Children

Children may be prescribed diuretics to reduce fluid overload caused by congestive heart failure and renal failure. The use of diuretics in children will depend on the treated condition. The dosage of diuretics in children is often calculated by body weight. 

Are diuretics safe?

Diuretics are generally safe medications when used as prescribed. Because of their effects on water, salt, and electrolyte reabsorption, they can cause fluid and electrolyte imbalances. Excess fluid loss can also lead to dehydration in some patients. Low potassium levels may also be a concern with many diuretics except potassium-sparing diuretics. 

The combined use of diuretics and digoxin or lithium may need to be monitored or avoided. Talk to a healthcare provider about other possible drug interactions with diuretics.

Diuretics recalls

There are no current diuretic recalls as of March 2021. 

Diuretics restrictions

Do not take diuretics if you have an allergy to ingredients in diuretics. Certain diuretics contain sulfa, which can cause an allergic reaction in people who have experienced an allergic reaction to sulfonamide medications like sulfamethoxazole. 

Some older people may need to be monitored while taking diuretics. Diuretics may increase the risk of dizziness or falls in older people due to postural hypotension, or a rapid decrease in blood pressure when changing sitting and standing positions. 

Can you take diuretics while pregnant or breastfeeding?

Diuretics are sometimes prescribed during pregnancy for hypertension or heart conditions. However, their safety has not been confirmed by studies. Diuretics should only be used if the benefits outweigh the risks. High doses of diuretics may affect the milk supply and suppress lactation in women who are breastfeeding. Consult a healthcare provider for medical advice before using diuretics while pregnant or breastfeeding. 

Are diuretics controlled substances?

No, diuretics are not controlled substances. 

Common diuretics side effects

The most common side effects of diuretics include:

• Frequent urination 

• Dizziness

• Lightheadedness

• Fatigue or tiredness

• Headache

• Rash

• Muscle cramps 

• Diarrhea

• Erectile dysfunction

• Increased blood sugar levels

Serious side effects of diuretics include low potassium levels, or hypokalemia, which can lead to abnormal heart rhythms. Without treatment, low potassium levels can lead to life-threatening problems. Potassium-sparing diuretics are less likely to cause this side effect but may instead cause high potassium levels (hyperkalemia). Diuretics can cause other electrolyte imbalances such as low sodium levels (hyponatremia) and low calcium levels (hypocalcemia). 

Diuretics may also cause dehydration due to the excretion of more fluids. Symptoms of dehydration may include extreme thirst, confusion, and dark-colored urine. 

Some diuretics such as thiazides may temporarily increase cholesterol levels.

Tell your doctor if you have a history of any of the following conditions before using a diuretic:

• Diabetes

• Gout

• Kidney problems

• Dehydration 

• Pancreatitis

• Lupus

• Menstrual problems

Talk to a healthcare provider to learn about other possible side effects, warnings, and precautions associated with diuretics. 

How much do diuretics cost?

Diuretics are generally cheap and affordable medications that are available in brand-name and generic versions. Almost all Medicare and insurance plans will cover diuretics. Costs can vary depending on your insurance plan. Without insurance, the cost of diuretics can vary depending on the quantity of tablets prescribed. However, using a prescription discount card from SingleCare may be able to help reduce the cost of diuretics.