What Is Chlorthalidone? Uses, Dosage, and What You Need to Know in 2026

Chlorthalidone is a prescription medication belonging to a class of drugs called thiazide-like diuretics, commonly known as "water pills." It has been used to treat high blood pressure and fluid retention since receiving FDA approval in 1960 — making it one of the longest-standing first-line hypertension treatments in medicine.

Despite being over 60 years old, chlorthalidone remains highly relevant. In fact, updated clinical guidelines and large clinical trials have reinforced its status as a preferred diuretic for blood pressure management.

What Is Chlorthalidone Used For?

The FDA has approved chlorthalidone for two primary indications:

High blood pressure (hypertension): Chlorthalidone is a first-line medication for treating hypertension, either alone or in combination with other blood pressure drugs. The 2017 ACC/AHA hypertension guidelines list thiazide-type diuretics — with chlorthalidone preferred — as one of the initial treatment options.

Edema (fluid retention): Chlorthalidone is used as adjunctive therapy for fluid buildup caused by congestive heart failure, liver cirrhosis, kidney disease, and certain hormone therapies (corticosteroids or estrogen).

Chlorthalidone is also used off-label for:

Calcium kidney stones (nephrolithiasis) — by reducing urinary calcium excretion

Diabetes insipidus (nephrogenic type)

Renal tubular acidosis

Brand Names and Generic

Chlorthalidone is primarily available as a generic medication. The brand-name Hygroton has been discontinued. Thalitone (available in 15 mg and 25 mg) and Hemiclor (12.5 mg) are brand versions that remain on the market, though they are expensive and rarely prescribed when generic is available. Most prescriptions today are filled as generic chlorthalidone tablets.

What Are the Available Doses?

Generic chlorthalidone tablets come in:

12.5 mg (Hemiclor brand; also available generic)

25 mg (most commonly prescribed)

50 mg (for edema and higher blood pressure needs)

Typical Dosing for Hypertension

For high blood pressure, the typical starting dose is 12.5–25 mg once daily. Clinical studies (including the landmark ALLHAT trial) showed that 12.5 mg daily had near-maximal blood pressure lowering effect — higher doses don't reduce blood pressure much more but do increase side effect risk.

Chlorthalidone is taken once daily, in the morning, with or without food. Because of its long half-life (40–60 hours), once-daily dosing provides consistent blood pressure control throughout the full 24-hour cycle.

Typical Dosing for Edema

For fluid retention (edema), doses are higher: typically 50–100 mg daily or 100 mg on alternate days, with a maximum of 200 mg per day. Higher doses are usually reserved for more significant fluid overload under specialist supervision.

Is Chlorthalidone a Controlled Substance?

No. Chlorthalidone is not a controlled substance. It has no DEA scheduling and no addiction potential. Any licensed prescriber (including nurse practitioners and physician assistants in most states) can prescribe it without special DEA registration. There are no restrictions on refills beyond standard prescription policies.

Who Should NOT Take Chlorthalidone?

Patients with anuria (inability to produce urine)

Patients with sulfonamide allergy (chlorthalidone is sulfonamide-derived)

Caution in severe kidney or liver disease

Caution in patients with gout (chlorthalidone can raise uric acid levels)

Caution in breastfeeding (may suppress lactation; use with caution)

How Much Does Chlorthalidone Cost?

Generic chlorthalidone is one of the most affordable blood pressure medications available. The average retail price is about $7–$46 for a 30-day supply, depending on the pharmacy and dose. With a GoodRx or SingleCare coupon, prices can drop to $2–$7 for a 30-day supply. With insurance, most patients pay $0–$30 per fill (Tier 1–2 on most formularies).

For a full breakdown of savings options, see our guide on how to save money on Chlorthalidone in 2026.

If you're having trouble finding chlorthalidone at your pharmacy, medfinder.com can help you locate which nearby pharmacies have it in stock.