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Chlortalidone

Hydrosan, Uldiulan · ATC code C03BA04

Also known as: Chlortalidon, Klortalidon, Clortalidone, Clortalidona · Brand names: Chlortalidon Axiromed, Chlortalidon Glenmark, Chlortalidon Hexal, Hygroton, Hydrosan, Uldiulan

Key facts
Active substance
Chlortalidone
Drug class
Diuretic
ATC code
C03BA04
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-11-03

Key facts

Chlortalidone (US spelling chlorthalidone) is a long-acting oral thiazide-like diuretic. Per the US label it is used for hypertension and as adjunctive therapy for oedema of cardiac, hepatic, renal or drug-induced origin.

What it is used for

  • Hypertension, alone or to enhance other antihypertensives
  • Adjunctive therapy of oedema in congestive heart failure, hepatic cirrhosis, and corticosteroid or oestrogen therapy
  • Oedema due to renal dysfunction (nephrotic syndrome, acute glomerulonephritis, chronic renal failure)

Dosing

  • Use the lowest effective dose; single dose in the morning with food
  • Hypertension: start 25 mg once daily, increase to 50 mg and then to 100 mg once daily or add a second antihypertensive; above 100 mg daily usually no added effect
  • Oedema (adults): initially 50 to 100 mg daily or 100 mg on alternate days; some patients need 150 to 200 mg at these intervals or up to 200 mg daily
  • Maintenance doses may be lower than initial doses

Contraindications

  • Anuria
  • Known hypersensitivity to chlortalidone or other sulfonamide-derived drugs

Important warnings

  • Severe renal disease: may precipitate azotaemia; cumulative effects in impaired renal function
  • Impaired hepatic function or progressive liver disease: electrolyte shifts may precipitate hepatic coma
  • Hypokalaemia (especially with brisk diuresis in cirrhosis or with corticosteroids/ACTH), hyponatraemia, hypochloraemic alkalosis, hypomagnesaemia; monitor electrolytes periodically
  • Hyperuricaemia or gout, hyperglycaemia and manifestation of latent diabetes; decreased calcium excretion
  • Sensitivity reactions in patients with allergy or asthma; possible exacerbation of SLE (reported with thiazides)

Side effects

  • Gastrointestinal: anorexia, nausea, vomiting, diarrhoea, constipation, cholestatic jaundice, pancreatitis
  • Dizziness, vertigo, paraesthesias, headache, orthostatic hypotension
  • Leucopenia, agranulocytosis, thrombocytopenia, aplastic anaemia
  • Photosensitivity, rash, urticaria, necrotising vasculitis, toxic epidermal necrolysis; hyperglycaemia, hyperuricaemia, muscle spasm, impotence

Interactions

  • Other antihypertensives: additive effect; potentiation with ganglionic or peripheral adrenergic blockers
  • Digitalis: hypokalaemia may exaggerate effects on the heart
  • Insulin and oral antidiabetics: requirements may change
  • Tubocurarine: increased responsiveness; norepinephrine: decreased arterial responsiveness; alcohol, barbiturates, narcotics may aggravate orthostatic hypotension

Pregnancy and breastfeeding

  • Use only if clearly needed; thiazides cross the placenta, with risk of fetal or neonatal jaundice and thrombocytopenia
  • Routine use for physiological oedema of pregnancy is inappropriate
  • Thiazides are excreted in human milk; decide between nursing and the drug

Summary of the official product information, written with AI on 2026-11-03. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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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.

Germany

  • Chlortalidon AxiromedMedical Valley Invest Ab · 1 register entry
  • Chlortalidon GlenmarkGlenmark Arzneimittel Gmbh · 1 register entry
  • Chlortalidon HexalHexal Ag · 1 register entry
  • HygrotonTrommsdorff Gmbh & Co. Kg · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-11-03

Austria

  • HydrosanWabosan Arzneimittelvertriebs Gmbh · 1 register entry
  • UldiulanG.L. Pharma Gmbh · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-11-03

Brand names in 14 more European countries
Belgium
Hygroton
Bulgaria
Zornichka, Зорничка, Улдиулан, Хлоротон
Croatia
Kataldi, Klortalidon Sandoz
Czechia
Uldiulan
Greece
Hygroton, Unidone
Hungary
Uldiulan
Italy
Igroton
Netherlands
Chloortalidon Focus Care, Chloortalidon Glenmark, Chloortalidon Teva, Chloortalidon Xiromed, Chlortalidone Aurobindo
Poland
Hygroton, Uldiulan
Portugal
Clorotalidona Farmoz, Clorotalidona Glenmark, Clorotalidona Tecnigen, Hygroton, Uldiulan
Romania
Uldiulan
Slovakia
Uldiulan
Spain
Clortalidona Glenmark, Higrotona
Sweden
Hygropax

EMA – Article 57 product data (EU/EEA), 2026-11-03

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Sources

  1. U.S. Food and Drug Administration. CHLORTHALIDONE (Rising Pharma Holdings, Inc.) – Prescribing Information, 2025-04-29. DailyMed (NLM), 2026-11-03. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=f96b2d0b-a141-4efb-8ccc-c447dfc6024a
  2. EMA – Article 57 product data (EU/EEA), 2026-11-03. 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), 2026-11-03. 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 C03BA.

Editorial: Medelix editorial team · last updated 2026-11-03 · 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.