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Hydrochlorothiazide

Hct G.L. · ATC code C03AA03

Also known as: Hydrochlorothiazid, Hidroklorotiyazid

Key facts
Active substance
Hydrochlorothiazide
Drug class
Thiazide
ATC code
C03AA03
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-29

Key facts

Hydrochlorothiazide is, per the US prescribing information, a thiazide diuretic used to treat edema of various causes and hypertension, alone or with other antihypertensive drugs.

What it is used for

  • Adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy.
  • Edema due to renal dysfunction such as nephrotic syndrome, acute glomerulonephritis and chronic renal failure.
  • Hypertension, alone or to enhance other antihypertensive drugs.

Dosing

  • Individualize therapy and use the smallest effective dose.
  • Edema (adults): usually 25 mg to 100 mg daily as a single or divided dose; many patients respond to intermittent therapy (alternate days or 3 to 5 days each week).
  • Hypertension (adults): start with 25 mg daily, may be increased to 50 mg daily; higher doses are often associated with marked reductions in serum potassium.
  • Children: 1 to 2 mg/kg per day, not exceeding 37.5 mg per day up to 2 years or 100 mg per day in children 2 to 12 years; infants under 6 months may need up to 3 mg/kg per day.

Contraindications

  • Anuria.
  • Hypersensitivity to this product or other sulfonamide-derived drugs.

Important warnings

  • Acute myopia and secondary angle-closure glaucoma within hours to weeks of starting; untreated, permanent vision loss can result.
  • Caution in severe renal disease (azotemia, accumulation) and impaired hepatic function (fluid and electrolyte shifts may precipitate hepatic coma).
  • Electrolyte disturbances such as hyponatremia, hypochloremic alkalosis, hypokalemia and hypomagnesemia; check electrolytes periodically.
  • Hyperuricemia or acute gout, hyperglycemia (latent diabetes may become manifest), increased cholesterol and triglycerides.
  • Increased risk of non-melanoma skin cancer; protect skin from the sun and have regular skin cancer screening.
  • Possible exacerbation or activation of systemic lupus erythematosus.

Side effects

  • No frequencies are given; reported reactions include weakness, (orthostatic) hypotension, pancreatitis, jaundice and gastrointestinal upset.
  • Blood disorders such as aplastic anemia, agranulocytosis, thrombocytopenia.
  • Hypersensitivity reactions, photosensitivity, Stevens-Johnson syndrome, toxic epidermal necrolysis.
  • Dizziness, headache, muscle spasm, renal failure, interstitial nephritis, impotence.

Interactions

  • Lithium should generally not be given with diuretics (high risk of lithium toxicity).
  • Cholestyramine and colestipol reduce hydrochlorothiazide absorption (by up to 85 and 43 percent).
  • Corticosteroids and ACTH intensify potassium loss; NSAIDs may reduce diuretic and antihypertensive effects.
  • Alcohol, barbiturates and narcotics may potentiate orthostatic hypotension; antidiabetic doses may need adjustment.

Pregnancy and breastfeeding

  • Routine use of diuretics in normal pregnancy is inappropriate; thiazides cross the placenta (risk of neonatal jaundice and thrombocytopenia, among others).
  • Thiazides are excreted in breast milk.

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

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For patients

Patient information (US)

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

Austria

  • Hct G.L.G.L. Pharma Gmbh · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-29

Germany

  • Hct089pharm Gmbh, 1 A Pharma Gmbh, Ratiopharm Gmbh, Dexcel Pharma Gmbh, Hexal Ag, Puren Pharma Gmbh & Co. Kg, Betapharm Arzneimittel Gmbh, Abz-Pharma Gmbh · 8 register entries

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-29

Brand names in 21 more European countries
Bulgaria
Hypodehydra, Дехидразид, Дехидратин Нео
Cyprus
Didralin, Hydrochlorothiazide Remedica
Czechia
Hydrochlorothiazid Léčiva
Denmark
Hydrochlorothiazide Orifarm, Hydromed
Estonia
Hypothiazid
Finland
Hydrex
France
Esidrex, Hydrochlorothiazide Arrow, Hydrochlorothiazide Biogaran, Hydrochlorothiazide Eg, Hydrochlorothiazide Gerda, Hydrochlorothiazide Sfdb, Hydrochlorothiazide Substipharm
Greece
Diuren, Losazide
Hungary
Hypothiazid
Iceland
Hydromed
Italy
Esidrex, Idroclorotiazide Aurobindo
Latvia
Hypothiazid
Lithuania
Hypothiazid
Netherlands
Hydrochloorthiazide
Norway
Esidrex, Hydrochlorothiazide Orifarm, Hydromed
Poland
Hydrochlorothiazide Aurovitas, Hydrochlorothiazidum Polpharma
Portugal
Hidroclorotiazida Bluefish, Hidroclorotiazida Generis
Romania
Nefrix
Slovakia
Hydrochlorothiazid Léčiva
Spain
Drine, Esidrex, Hidroclorotiazida Aristo, Hidroclorotiazida Aurovitas, Hidroclorotiazida Cinfa, Hidroclorotiazida Gobens, Hidroclorotiazida Kern Pharma, Hidroclorotiazida Normon, Hidroclorotiazida Sandoz, Hidroclorotiazida Stada, Hidroclorotiazida Vir, Hidrosaluretil
Sweden
Esidrex, Hydrochlorothiazide Bluefish, Hydrochlorothiazide Orifarm, Hydroklortiazid Evolan

EMA – Article 57 product data (EU/EEA), 2026-10-29

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Sources

  1. U.S. Food and Drug Administration. Hydrochlorothiazide (Unichem Pharmaceuticals (USA), Inc.) – Prescribing Information, 2025-06-13. DailyMed (NLM), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=33f3b980-b339-4dbf-99bd-05588c2a298c
  2. EMA – Article 57 product data (EU/EEA), 2026-10-29. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  3. EMA – Article 57 product data (EU/EEA), 2026-10-29. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  4. Wikidata (CC0): ATC C03AA.

Editorial: Medelix editorial team · last updated 2026-10-29 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.