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- Mark Abramowicz, M.D., President has disclosed no relevant financial relationships.
- Jean-Marie Pflomm, Pharm.D., Editor in Chief has disclosed no relevant financial relationships.
- Discuss the efficacy of the new 12.5-mg dose of chlorthalidone (HemiClor) for treatment of hypertension.
The FDA has approved a 12.5-mg tablet formulation of the thiazide-like diuretic chlorthalidone (HemiClor – Ingenus) for treatment of hypertension. Chlorthalidone has been available for years in 15-, 25-, and 50-mg tablets (Thalitone, and generics) and in fixed-dose combinations with azilsartan medoxomil (Edarbyclor) and atenolol (Tenoretic, and generics).1,2
CHLORTHALIDONE — Chlorthalidone is more potent than the thiazide diuretic hydrochlorothiazide (HCTZ) and it has a longer half-life. Chlorthalidone and HCTZ appear to be similarly effective in improving outcomes in patients with hypertension,3-5 but chlorthalidone is more likely to cause hypokalemia. Current guidelines recommend chlorthalidone at a dose of 12.5-25 mg once daily for treatment of hypertension.6
A CLINICAL STUDY — FDA approval of the 12.5-mg formulation was based on data from an 8-week double-blind trial in 1714 adults with hypertension who were randomized to receive one of six fixed-dose combinations of azilsartan medoxomil and chlorthalidone or the individual components alone. Monotherapy with chlorthalidone 12.5 mg was similar in efficacy to the 25-mg dose with fewer adverse effects.7
COST — The wholesale acquisition cost (WAC) of a 30-day supply of HemiClor is $30; cutting a 25-mg tablet of generic chlorthalidone in half costs much less ($3 for 15 25-mg tablets) but may be difficult for some patients.8
CONCLUSION — The new low-dose formulation of chlorthalidone (HemiClor) offers a convenient way to administer a 12.5-mg dose without having to split a higher-strength tablet.
- Edarbyclor: an ARB/chlorthalidone combination for hypertension. Med Lett Drugs Ther 2012; 54:17.
- Drugs for hypertension. Med Lett Drugs Ther 2024; 66:81.
- A Ishani et al. Chlorthalidone vs. hydrochlorothiazide for hypertension-cardiovascular events. N Engl J Med 2022; 387:2401. doi:10.1056/nejmoa2212270
- A Ishani et al. Chlorthalidone vs hydrochlorothiazide and kidney outcomes in patients with hypertension: a secondary analysis of a randomized clinical trial. JAMA Netw Open 2024; 7:e2449576. doi:10.1001/jamanetworkopen.2024.49576
- G Hripcsak et al. Comparison of cardiovascular and safety outcomes of chlorthalidone vs hydrochlorothiazide to treat hypertension. JAMA Intern Med 2020; 180:542. doi:10.1001/jamainternmed.2019.7454
- PK Whelton et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on clinical practice guidelines. J Am Coll Cardiol 2018; 71:2199. doi:10.1016/j.jacc.2017.11.005
- D Sica et al. Blood pressure-lowering efficacy of the fixed-dose combination of azilsartan medoxomil and chlorthalidone: a factorial study. J Clin Hypertens (Greenwich) 2012; 14:284. doi:10.1111/j.1751-7176.2012.00616.x
- Approximate WAC. WAC = wholesaler acquisition cost or manufacturer's published price to wholesalers; WAC represents a published catalogue or list price and may not represent an actual transactional price. Source: AnalySource® Monthly. June 5, 2025. Reprinted with permission by First Databank, Inc. All rights reserved. ©2025. www.fdbhealth.com/policies/drug-pricing-policy.
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