What is Chlorthalidone?

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Last updated: February 10, 2025View editorial policy

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From the Guidelines

Chlorthalidone is a thiazide-like diuretic used to treat hypertension.

Key Characteristics of Chlorthalidone

  • It is a long-acting diuretic with a prolonged half-life, which makes it effective for once-daily dosing 1.
  • The usual dose range is 12.5-25 mg/day, taken once daily 1.
  • Chlorthalidone is preferred over other diuretics due to its proven reduction of cardiovascular disease (CVD) events in clinical trials 1.
  • It is often used as a first-line treatment for hypertension, either as monotherapy or in combination with other antihypertensive agents 1.

Important Considerations

  • Chlorthalidone can cause hypokalemia (low potassium levels) and hypomagnesemia (low magnesium levels), so monitoring of electrolyte levels is recommended 1.
  • It may also increase the risk of hyponatremia (low sodium levels) and hyperuricemia (high uric acid levels) 1.
  • Chlorthalidone is generally well-tolerated, but patients should be monitored for potential side effects, such as dizziness and headache.

Clinical Use

  • Chlorthalidone is commonly used in combination with other antihypertensive agents, such as ACE inhibitors, ARBs, and CCBs, to achieve optimal blood pressure control 1.
  • It is also used in patients with heart failure, chronic kidney disease, and diabetes, but with careful monitoring of electrolyte levels and kidney function 1.

From the FDA Drug Label

Chlorthalidone is an oral diuretic with prolonged action (48-72 hours) and low toxicity. Chlorthalidone is an oral antihypertensive/diuretic. It is a monosulfamyl diuretic that differs chemically from thiazide diuretics in that a double-ring system is incorporated in its structure.

Chlorthalidone is an oral diuretic and antihypertensive medication. It is a type of monosulfamyl diuretic that is used to produce copious diuresis with increased excretion of sodium and chloride 2, 2.

From the Research

Definition and Use of Chlorthalidone

  • Chlorthalidone is a thiazide diuretic used in the treatment of hypertension, either as monotherapy or in combination with other antihypertensive compounds 3.
  • It has a longer half-life and a wider volume of distribution compared to hydrochlorothiazide, which affords it a unique advantage in its capacity to act as an effective diuretic and blood-pressure-lowering agent 3.

Comparison with Hydrochlorothiazide

  • Chlorthalidone is currently recommended as the preferred thiazide diuretic to treat hypertension, but studies have shown that it may not have significant cardiovascular benefits compared to hydrochlorothiazide 4.
  • Chlorthalidone has been associated with a higher risk of hypokalemia, hyponatremia, acute renal failure, chronic kidney disease, and type 2 diabetes mellitus compared to hydrochlorothiazide 4.
  • However, chlorthalidone has also been shown to have a lower risk of diagnosed abnormal weight gain compared to hydrochlorothiazide 4.

Clinical Considerations

  • The choice between chlorthalidone and hydrochlorothiazide should be based on individual patient characteristics and the potential for side effects 5.
  • Chlorthalidone has limited pharmaceutical formulations, but there are other evidence-based, single-tablet, alternative diuretics that may be considered 6.
  • The American College of Cardiology recommends chlorthalidone over hydrochlorothiazide as a first-line treatment for hypertension, but this recommendation may need to be reevaluated based on recent studies 5.

Pharmacokinetic and Pharmacodynamic Differences

  • Chlorthalidone is approximately 1.5 to 2.0 times as potent as hydrochlorothiazide, and has a much longer duration of action 7.
  • These pharmacokinetic and pharmacodynamic differences may cause differences in outcomes, but further study is needed to fully understand their clinical significance 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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