II. Indications
III. Dosing: Hypertension (Adults)
- Start: 12.5 to 25 mg orally daily
- Maximum: 50 mg/day
- Higher doses worsen Hypokalemia without additional Antihypertensive benefit
IV. Efficacy
- May be preferred over Hydrochlorothiazide
- Longer half life than immediate release Hydrochlorothiazide
- Two to three times as potent as Hydrochlorothiazide
- Chlorthalidone lowers systolic Blood Pressure 10 mmHg more than Hydrochlorothiazide
- However, 2022 study shows similar cardiovascular outcomes with Hydrochlorothiazide
- Chlorthalidone is more likely to result in Hypokalemia (see below)
- Conversion: Use 12.5 mg of Chlorthalidone in place of 25 mg Hydrochlorothiazide
V. Precautions
- Monitor Serum Potassium at baseline, 2 weeks and every 6-12 months (increased Hypokalemia risk)
- Decrease Sodium intake
- High Sodium intake is associated with increased Potassium losses
- Also associated with worse Blood Pressure control)
- Consider Potassium Supplementation
- Avoid if on Potassium sparing agents or significant Chronic Kidney Disease
- Potassium chloride 20 meq orally daily for Hypokalemia or prevention of Hypokalemia or
- Dietary Potassium for prevention of Hypokalemia
- Consider using Chlorthalidone in combination with agents balance Potassium losses
- Additional Blood Pressure lowering required
- No additional Blood Pressure lowering required
VI. Pharmacokinetics
- Onset of activity: 2 hours
- Duration >24 hours
VII. Mechanism
VIII. Adverse Effects
IX. Safety
- Pregnancy Category B
- Pregnancy Category D if used for Pregnancy Induced Hypertension
- Unknown Safety in Lactation
X. Resources
- Chlorthalidone (DailyMed)
XI. References
- (2012) Presc Lett 19(2): 8
- (2014) Presc Lett 21(9): 52
- (2021) Presc Lett, Resource #370507, Commonly Used Diuretics
- (2020) Med Lett Drugs Ther 62(1598): 73-80
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 62-3
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
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Related Studies
| chlorthalidone (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| CHLORTHALIDONE 25 MG TABLET | Generic | $0.11 each |
| CHLORTHALIDONE 50 MG TABLET | Generic | $0.14 each |