Table of ContentsView AllTable of ContentsSimilarities and DifferencesHow Well They WorkDosageElectrolyte ImbalanceCombination Drugs
Table of ContentsView All
View All
Table of Contents
Similarities and Differences
How Well They Work
Dosage
Electrolyte Imbalance
Combination Drugs
Chlorthalidone and hydrochlorothiazide (HCTZ) are both thiazide diuretics used as a cornerstone treatment for hypertension (high blood pressure).
Even though chlorthalidone and hydrochlorothiazide are structurally similar compounds, they are quite different. They differ in their dosing regimen, potency (strength), duration of action, and side effects. There is also a huge difference in the prescription ratio of these drugs. HCTZ is the preferred choice in most cases.
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Main Similarities and Differences
Approved to treat high blood pressure and edema (swelling)
Available alone and in combination pills
Effective options for lowering blood pressure
DifferencesHCTZ is prescribed more frequentlyChlorthalidone is stronger and lasts longer in the bodyChlorthalidone has a higher risk of kidney and electrolyte problems with use
HCTZ is prescribed more frequently
Chlorthalidone is stronger and lasts longer in the body
Chlorthalidone has a higher risk of kidney and electrolyte problems with use
How Well Do They Work?
Thiazide diuretics have been commonly used as first-line agents for the treatment of hypertension. They have proven effective at lowering blood pressure, being safe, and being low cost.
These drugs are both proven effective at treating high blood pressure. While previous studies have suggested chlorthalidone works better, newer research indicates they are equally effective in treating cardiovascular problems.
However, other studies suggest that chlorthalidone is stronger and has a longer duration of action. But it has a higher risk of side effects, such aselectrolyte imbalance.
Usually, HCTZ is the preferred choice of healthcare professionals. HCTZ is prescribed more often than chlorthalidone.
When it comes to prescribing decisions, healthcare providers weigh the benefits and risks of each medication to help achieve therapeutic targets.
Effects on Heart Disease Risk and Mortality
Chlorthalidone may have a few additional benefits for high blood pressure than HCTZ. However, these drugs are equally effective in studies on their effects on heart disease risk and mortality.
A study shows no significant differences in the risk of acutemyocardial infarction(heart attack), hospitalizedheart failure,stroke, or cardiovascular problems between individuals receiving chlorthalidone and hydrochlorothiazide.
Another analysis showed that chlorthalidone was better than hydrochlorothiazide at controlling blood pressure. But there was no significant difference between the two for the risk of heart attack, stroke,all-cause mortality,and hospitalization due to heart failure.
Other Uses
Chlorthalidone and hydrochlorothiazide may also be used to treat edema (fluid retention),diabetes insipidus, and preventkidney stonesin people with high calcium levels in their blood.
Can You Use Chlorthalidone and HCTZ Together?Usually, your healthcare provider will prescribe either chlorthalidone or HCTZ. These drugs have the same action mechanism, so taking them together can lead to side effects. While not used together, chlorthalidone and HCTZ can each be combined with other active ingredients to make combination drugs to treat blood pressure.
Can You Use Chlorthalidone and HCTZ Together?
Usually, your healthcare provider will prescribe either chlorthalidone or HCTZ. These drugs have the same action mechanism, so taking them together can lead to side effects. While not used together, chlorthalidone and HCTZ can each be combined with other active ingredients to make combination drugs to treat blood pressure.
Chlorthalidone and HCTZ are available in tablet formulations that can be taken orally. Chlorthalidone is available in 25 milligram (mg) or 50 mg strength tablets. HCTZ comes in 12.5 mg, 25 mg, and 50 mg.
Dosing for both involves an initial dosage and then a maintenance dose, which may be lower than the starting dosage and adjusted accordingly.
How Long Chlorthalidone and HCTZ Last in the Body
On the other hand, chlorthalidone lasts longer in the body than other diuretics, including HCTZ. It starts working within two to three hours, and its effects last up to 72 hours.
Risk of Electrolyte Imbalances
Diuretics can cause anelectrolyte imbalance. An electrolyte imbalance occurs when the amount of electrolytes (important minerals such as potassium, sodium, and calcium) in the blood falls out of range.
All people taking diuretics should be observed for fluid or electrolyte imbalance, including:
This risk is based on the dose of your medication and varies based on the diuretic.It may lead to syncope (fainting) and falls.
The risk of hyponatremia is usually higher with chlorthalidone when compared with hydrochlorothiazide.
How to Prevent Electrolyte Imbalances
When taking diuretics, keep a close check on symptoms of electrolyte imbalance, such as:
In addition to water, ORS contains specific amounts of glucose and electrolytes, potassium, and sodium. These components maximize fluid absorption in the gastrointestinal tract.
In case of severe symptoms, seek immediate medical help. Your healthcare provider will provide treatments for electrolyte imbalances, including:
Availability in Combination Medications
Sometimes, it is quite a task to manage blood pressure with a single drug therapy. Your healthcare provider may prescribe more than one medicine or a combination pill containing two different drugs.
Chlorthalidone and HCTZ are individually combined with other blood pressure drugs in combination medications. These include diuretics withangiotensin-converting enzyme (ACE)inhibitors, angiotensin II receptor blockers (ARBs), orcalcium channel blockers.
Here are some common examples that include HCTZ with other drugs:
Chlorthalidone is available in the following combination pills:
Summary
These drugs work similarly to excrete excess water and salt from the body into the urine. However, they differ in their doses, duration of action and side effects.
Although they are nearly equally effective in treating the indications, some studies prefer one drug over the other. Your healthcare provider will determine the best treatment for you, considering the potential benefits and side effects.
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Khenhrani RR, Nnodebe I, Rawat A, et al.Comparison of the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension: a meta-analysis.Cureus. 2023;15(4):e38184. doi:10.7759/cureus.38184MedlinePlus.Chlorthalidone.MedlinePlus.Hydrochlorothiazide.Ishani A, Cushman WC, Leatherman SM, et al.Chlorthalidone vs. hydrochlorothiazide for hypertension–cardiovascular events.N Engl J Med.2022;387(26):2401-2410. doi:10.1056/NEJMoa2212270Hripcsak G, Suchard MA, Shea S, et al.Comparison of cardiovascular and safety outcomes of chlorthalidone vs hydrochlorothiazide to treat hypertension.JAMA Intern Med.2020;180(4):542-551.doi:10.1001/jamainternmed.2019.7454DailyMed.Label: Hydrochlorothiazide tablet.DailyMed.Label: Chlorthalidone tablets.Ravioli S, Bahmad S, Funk GC, et al.Risk of electrolyte disorders, syncope, and falls in patients taking thiazide diuretics: results of a cross-sectional study.Am J Med.2021;134(9):1148-1154. doi:10.1016/j.amjmed.2021.04.007.van Blijderveen JC, Straus SM, Rodenburg EM, et al.Risk of hyponatremia with diuretics: chlorthalidone versus hydrochlorothiazide.Am J Med. 2014;127(8):763-y71. doi:10.1016/j.amjmed.2014.04.014Balcı AK, Koksal O, Kose A, et al.General characteristics of patients with electrolyte imbalance admitted to emergency department.World J Emerg Med. 2013;4(2):113-116. doi:10.5847/wjem.j.issnAghsaeifard Z, Heidari G, Alizadeh R.Understanding the use of oral rehydration therapy: a narrative review from clinical practice to main recommendations.Health Sci Rep. 2022;5(5):e827. doi:10.1002/hsr2.827
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Khenhrani RR, Nnodebe I, Rawat A, et al.Comparison of the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension: a meta-analysis.Cureus. 2023;15(4):e38184. doi:10.7759/cureus.38184MedlinePlus.Chlorthalidone.MedlinePlus.Hydrochlorothiazide.Ishani A, Cushman WC, Leatherman SM, et al.Chlorthalidone vs. hydrochlorothiazide for hypertension–cardiovascular events.N Engl J Med.2022;387(26):2401-2410. doi:10.1056/NEJMoa2212270Hripcsak G, Suchard MA, Shea S, et al.Comparison of cardiovascular and safety outcomes of chlorthalidone vs hydrochlorothiazide to treat hypertension.JAMA Intern Med.2020;180(4):542-551.doi:10.1001/jamainternmed.2019.7454DailyMed.Label: Hydrochlorothiazide tablet.DailyMed.Label: Chlorthalidone tablets.Ravioli S, Bahmad S, Funk GC, et al.Risk of electrolyte disorders, syncope, and falls in patients taking thiazide diuretics: results of a cross-sectional study.Am J Med.2021;134(9):1148-1154. doi:10.1016/j.amjmed.2021.04.007.van Blijderveen JC, Straus SM, Rodenburg EM, et al.Risk of hyponatremia with diuretics: chlorthalidone versus hydrochlorothiazide.Am J Med. 2014;127(8):763-y71. doi:10.1016/j.amjmed.2014.04.014Balcı AK, Koksal O, Kose A, et al.General characteristics of patients with electrolyte imbalance admitted to emergency department.World J Emerg Med. 2013;4(2):113-116. doi:10.5847/wjem.j.issnAghsaeifard Z, Heidari G, Alizadeh R.Understanding the use of oral rehydration therapy: a narrative review from clinical practice to main recommendations.Health Sci Rep. 2022;5(5):e827. doi:10.1002/hsr2.827
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Khenhrani RR, Nnodebe I, Rawat A, et al.Comparison of the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension: a meta-analysis.Cureus. 2023;15(4):e38184. doi:10.7759/cureus.38184MedlinePlus.Chlorthalidone.MedlinePlus.Hydrochlorothiazide.Ishani A, Cushman WC, Leatherman SM, et al.Chlorthalidone vs. hydrochlorothiazide for hypertension–cardiovascular events.N Engl J Med.2022;387(26):2401-2410. doi:10.1056/NEJMoa2212270Hripcsak G, Suchard MA, Shea S, et al.Comparison of cardiovascular and safety outcomes of chlorthalidone vs hydrochlorothiazide to treat hypertension.JAMA Intern Med.2020;180(4):542-551.doi:10.1001/jamainternmed.2019.7454DailyMed.Label: Hydrochlorothiazide tablet.DailyMed.Label: Chlorthalidone tablets.Ravioli S, Bahmad S, Funk GC, et al.Risk of electrolyte disorders, syncope, and falls in patients taking thiazide diuretics: results of a cross-sectional study.Am J Med.2021;134(9):1148-1154. doi:10.1016/j.amjmed.2021.04.007.van Blijderveen JC, Straus SM, Rodenburg EM, et al.Risk of hyponatremia with diuretics: chlorthalidone versus hydrochlorothiazide.Am J Med. 2014;127(8):763-y71. doi:10.1016/j.amjmed.2014.04.014Balcı AK, Koksal O, Kose A, et al.General characteristics of patients with electrolyte imbalance admitted to emergency department.World J Emerg Med. 2013;4(2):113-116. doi:10.5847/wjem.j.issnAghsaeifard Z, Heidari G, Alizadeh R.Understanding the use of oral rehydration therapy: a narrative review from clinical practice to main recommendations.Health Sci Rep. 2022;5(5):e827. doi:10.1002/hsr2.827
Khenhrani RR, Nnodebe I, Rawat A, et al.Comparison of the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension: a meta-analysis.Cureus. 2023;15(4):e38184. doi:10.7759/cureus.38184
MedlinePlus.Chlorthalidone.
MedlinePlus.Hydrochlorothiazide.
Ishani A, Cushman WC, Leatherman SM, et al.Chlorthalidone vs. hydrochlorothiazide for hypertension–cardiovascular events.N Engl J Med.2022;387(26):2401-2410. doi:10.1056/NEJMoa2212270
Hripcsak G, Suchard MA, Shea S, et al.Comparison of cardiovascular and safety outcomes of chlorthalidone vs hydrochlorothiazide to treat hypertension.JAMA Intern Med.2020;180(4):542-551.doi:10.1001/jamainternmed.2019.7454
DailyMed.Label: Hydrochlorothiazide tablet.
DailyMed.Label: Chlorthalidone tablets.
Ravioli S, Bahmad S, Funk GC, et al.Risk of electrolyte disorders, syncope, and falls in patients taking thiazide diuretics: results of a cross-sectional study.Am J Med.2021;134(9):1148-1154. doi:10.1016/j.amjmed.2021.04.007.
van Blijderveen JC, Straus SM, Rodenburg EM, et al.Risk of hyponatremia with diuretics: chlorthalidone versus hydrochlorothiazide.Am J Med. 2014;127(8):763-y71. doi:10.1016/j.amjmed.2014.04.014
Balcı AK, Koksal O, Kose A, et al.General characteristics of patients with electrolyte imbalance admitted to emergency department.World J Emerg Med. 2013;4(2):113-116. doi:10.5847/wjem.j.issn
Aghsaeifard Z, Heidari G, Alizadeh R.Understanding the use of oral rehydration therapy: a narrative review from clinical practice to main recommendations.Health Sci Rep. 2022;5(5):e827. doi:10.1002/hsr2.827
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