Thiazide diuretics: Uses, common brands, and safety info
Diuretics, also known as water pills, increase the amount of water and salt, or sodium, eliminated from the body by increasing urination frequency and amount. The three types of diuretics are thiazide diuretics, loop diuretics, and potassium-sparing diuretics. They are commonly prescribed to treat high blood pressure, also known as hypertension.
Until 1957, the only diuretics available contained mercury and had to be given by injection. They were difficult to use and mostly limited to patients experiencing heart failure. In the 1950s, research scientists at the drug company Merck Sharp & Dohme discovered chlorothiazide, intended for use in patients with heart failure. Within a few weeks of use in a small number of patients, it was apparent that chlorothiazide lowered blood pressure. Since then, thiazide diuretics have been considered the cornerstone of therapy for treating high blood pressure.
The following table lists commonly used thiazide diuretics followed by information on how they work, what conditions they treat, safety, and cost.
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List of thiazide diuretics
| Drug name | Learn more | See SingleCare price |
|---|---|---|
| Chlorthalidone | chlorthalidone details |  |
| Diuril | diuril details | |
| Hydrochlorothiazide | hydrochlorothiazide details | |
| Indapamide | indapamide details | |
| Metolazone | metolazone details | |
Other thiazide diuretics
Bendroflumethiazide
Methyclothiazide
Thiazide/diuretic combinations:
Hydralazine-hydrochlorothiazide
Angiotensin receptor blocker (ARB)/thiazide combinations:
Angiotensin-converting-enzyme (ACE) inhibitors/thiazide combinations:
What are thiazide diuretics?
Thiazide diuretics are a class of drugs that have been effectively used for more than 60 years in the management of high blood pressure. Their use as a single-drug therapy or in combination with other antihypertensive drugs has resulted in dramatic decreases in cerebrovascular events, such as stroke, and in cardiovascular events, such as heart attacks. When comparing clinical data with other classes of high blood pressure medications, thiazide diuretics are as good or even more effective in preventing strokes and heart attacks.
How do thiazide diuretics work?
High blood pressure is a common condition in which the blood pumps with too much force against the artery, or blood vessel, walls. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure. The force against the artery walls may become high enough to eventually cause health problems to the heart or arteries, i.e., heart disease, or to the blood vessels in the brain, which can lead to a stroke.
One of the effects of thiazide diuretics is to make the kidneys pass more fluid to the bladder so that you urinate more, thereby reducing the amount of fluid the heart has to pump. This occurs by interfering with the transfer of salt and water across certain cells in the kidneys. Thiazide diuretics can also widen blood vessels, which reduces the resistance to the blood flowing through the arteries. The combination of these two effects results in a reduction in blood pressure. When thiazide diuretics are used in combination with other medications—such as beta blockers, angiotensin II receptor blockers (ARBs), or angiotensin-converting enzyme inhibitors (ACE inhibitors)—blood pressure-lowering may be even greater.
RELATED: List of calcium channel blockers
What are thiazide diuretics used for?
Thiazide diuretics are approved by the U.S. Food and Drug Administration (FDA) for the following conditions:
Fluid retention, or edema, in people with congestive heart failure
Fluid retention in people with the kidney disorder nephrotic syndrome
Fluid retention in people with cirrhosis of the liver
Fluid retention caused by taking steroids or estrogen
Thiazide diuretics are also used off-label, i.e., not FDA approved uses, for the following conditions:
Nephrolithiasis (kidney stones)
Osteoporosis (brittle or fragile bones)
Diabetes insipidus (an imbalance of fluids in the body leading to the production of large amounts of urine)
Who can take thiazide diuretics?
Children and adolescents
Thiazide diuretics are often prescribed to children to reduce body fluid in disease states such as congestive heart failure and renal failure. As with many drugs used in children, there is no fixed dose amount and dosing is typically calculated by body weight. The American Academy of Pediatrics provides guidelines for initiating high blood pressure treatments, including thiazide diuretics, in children.
Adults
Thiazide diuretics are commonly used to treat edema and other cardiovascular conditions in adults. Generally, for high blood pressure treatment, thiazide diuretics require a lower starting dosage and may be increased based on the individual therapeutic needs of the patient. For adults experiencing fluid buildup and edema, high doses may be necessary. The American Society of Nephrology provides guidelines on the treatment of high blood pressure with thiazide diuretics.
Pregnancy and breastfeeding
It is not known whether thiazide diuretics can cause fetal harm when administered to a pregnant woman although it has been shown that the medicines cross the placental barrier. Thiazide diuretics should only be used during pregnancy if the benefits outweigh the risks.
Although the information is limited, hydrochlorothiazide doses of 50 mg daily or less are generally considered safe for breastfed infants. There is, however, the potential for adverse effects in nursing infants while on a thiazide diuretic, therefore the decision should be made whether to discontinue nursing or to discontinue the drug based on benefit versus risk.
A woman’s healthcare provider is the best source of information when managing diuretic treatment during pregnancy or while breastfeeding.
Seniors
Although there are few clinical trials in patients older than 65, diuretics can effectively lower blood pressure in older adults. Older patients may start with low-dose treatment due to their greater likelihood of liver and kidney dysfunction. Since thiazide diuretics are known to be mostly excreted by the kidney, it is recommended that kidney function be monitored in seniors.
Are thiazide diuretics safe?
After 60 years of use, thiazide diuretics remain an effective and safe therapeutic choice in the treatment of hypertension and edema. Additionally, their ability to increase the efficacy of many other classes of high blood pressure drugs makes them a valuable therapeutic option in the treatment of hypertension.
However, the following drugs may interact with thiazide diuretics:
Lithium combined with thiazide diuretics may increase the risk of lithium toxicity and is not recommended.
Alcohol and other CNS depressants may increase the chance of thiazide diuretics causing orthostatic hypotension (dizziness or faintness due to low blood pressure when standing up quickly from a sitting or lying position).
Diabetes medicines given concurrently may need a dose adjustment.
Other high blood pressure medicines may have an additive effect in lowering blood pressure.
Corticosteroids may increase electrolyte loss, importantly resulting in hypokalemia (low blood calcium levels).
This is not a complete list of potential drug-drug interactions. Talk to your healthcare provider about other possible drug interactions with thiazide diuretics.
Recalls
Restrictions
The presence of other medical problems and conditions may affect the use of thiazide diuretics. You should not use thiazide diuretics if you have any of the following conditions:
Hypotension (low blood pressure)
Allergy to sulfa drugs
Gout
Hypokalemia (low blood potassium levels)
Kidney failure
Anuria (unable to form urine)
Thiazide diuretics should be used with caution if you have any of the following conditions:
Asthma
Diabetes
Hypercalcemia (high calcium in the blood)
Hypochloremia (low chloride in the blood)
Hypomagnesemia (low magnesium in the blood)
Hyponatremia (low sodium in the blood)
Hypophosphatemia (low phosphorus in the blood)
Liver disease
Systemic lupus erythematosus
Kidney disease
Are thiazide diuretics controlled substances?
No, thiazide diuretics are not controlled substances.
Common thiazide diuretics side effects
Side effects of thiazide diuretics are usually dose-related and include:
Dizziness and lightheadedness
Blurred vision
Loss of appetite
Itching
Stomach upset
Headache
Weakness
Serious, although uncommon, side effects include:
Hypokalemia, or low blood potassium levels, which can be life-threatening
Hyponatremia, or low blood sodium levels, which may occur during the first two to three weeks of diuretic therapy
Metabolic alkalosis, a condition that occurs when the blood becomes overly alkaline, which may cause nausea and vomiting
Hyperglycemia, or high blood glucose levels, may lead to increased thirst, blurred vision, frequent urination, or headache.
Hyperuricemia, or high blood uric acid levels, which may increase the risk of developing gout
Hyperlipidemia, or a high
level of fats or lipids in the blood
Increased risk of developing acute pancreatitis, or inflammation of the pancreas
How much do thiazide diuretics cost?
Because thiazide diuretics are all available in generic versions, they are generally considered very affordable. For example, chlorthalidone costs approximately $31 for a supply of 30, 25 mg tablets. Most Medicare and insurance plans will cover thiazide diuretics; however, costs can vary depending on your insurance plan. Using a prescription discount card from SingleCare may help reduce the cost of thiazide diuretics.
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