What does chlorothiazide mean?
Chlorothiazide is a prescription medication belonging to the thiazide class of diuretics — drugs commonly called 'water pills' because they increase the amount of water and salt the body eliminates through urine. Acting on the distal tubules of the kidney, it blocks sodium reabsorption, which in turn draws out excess fluid and lowers blood pressure. Introduced commercially in the late 1950s under the brand name Diuril, it was the pioneering member of its class and helped make hypertension and congestive edema routinely treatable for the first time. Today it is less frequently prescribed than newer relatives such as hydrochlorothiazide, but it remains clinically relevant. Because the word belongs to technical medicine, it surfaces mainly in prescriptions, pharmacology texts, and patient information leaflets. Its chemical name reflects its structure: a sulfonamide-derived ring bearing chlorine and nitrogen atoms.
nounA synthetic thiazide diuretic drug that promotes the excretion of water and sodium by the kidneys, used chiefly to treat hypertension and edema. It was the first of the benzothiadiazine diuretics to be marketed.
- A thiazide diuretic drug (C₇H₆ClN₃O₄S₂) that increases urinary excretion of water and electrolytes, used to treat hypertension and edema.
"The physician added a low dose of chlorothiazide to the patient's regimen to bring her blood pressure under control."
"Because it promotes sodium and water loss, chlorothiazide can lower blood pressure within days of starting treatment."
"The cardiologist noted that long-term use of chlorothiazide could deplete potassium, so she ordered regular blood tests."
Rarely used; typically reserved for references to multiple doses, formulations, or members of the drug class.
"The formulary stocked several chlorothiazides in varying tablet strengths."
Introduced in the late 1950s as the first 'water pill' of the thiazide class, chlorothiazide helped transform high blood pressure from an often untreatable condition into a manageable one.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chlorothiazide
The name chlorothiazide is a modern scientific coinage built from Greek roots: 'chloro-' from Greek chlōros ('pale green'), reflecting the presence of chlorine in the molecule, combined with 'thiazide', derived from thiazole, a five-membered heterocyclic ring whose name blends 'thio-' (Greek theion, sulfur) with 'azole'. The term emerged in American pharmaceutical literature in the mid-1950s, when researchers at Merck developed the first benzothiadiazine diuretics. Related coinages include hydrochlorothiazide and other members of the same drug family, all sharing the '-thiazide' suffix.
Related word forms
How chlorothiazide is actually used
Strictly a technical medical term; it appears almost exclusively in pharmacology, clinical practice, and drug labeling rather than everyday conversation. It is uncountable in ordinary use, though plural forms occur when referring to multiple doses or formulations.
Easily confused with chlorothiazide
Hydrochlorothiazide is a related but chemically distinct thiazide diuretic that is more potent milligram-for-milligram than chlorothiazide.