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Sulfasalazine

Salazopyrin · ATC code A07EC01

Also known as: Sulfasalazin, Sülfasalazin · Brand names: Salazopyrin, Azulfidine, Sulfasalazin Hexal, Sulfasalazin Heyl, Sulfasalazin Medac, Kolilet, Azulfidine EN-tabs

Key facts
Active substance
Sulfasalazine
Drug class
Antidiarrhoeal
ATC code
A07EC01
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-29

Key facts

Sulfasalazine is, per the US prescribing information, an anti-inflammatory drug (split into sulfapyridine and 5-aminosalicylic acid) used to treat ulcerative colitis and to prolong remission.

What it is used for

  • Mild to moderate ulcerative colitis, and adjunctive therapy in severe ulcerative colitis.
  • Prolongation of the remission period between acute attacks of ulcerative colitis.

Dosing

  • Adults, initial therapy: 3 to 4 g daily in evenly divided doses no more than eight hours apart; starting with 1 to 2 g daily may reduce gastrointestinal intolerance; above 4 g daily the risk of toxicity increases.
  • Adults, maintenance: 2 g daily.
  • Children six years and older: initially 40 to 60 mg/kg per 24 hours in 3 to 6 doses, maintenance 30 mg/kg per 24 hours in 4 doses.
  • For gastric intolerance, halve the daily dose and increase it gradually; if it persists, stop for 5 to 7 days.
  • Desensitization regimens for sensitive patients – see the full text.

Contraindications

  • Intestinal or urinary obstruction.
  • Porphyria.
  • Hypersensitivity to sulfasalazine, its metabolites, sulfonamides or salicylates.

Important warnings

  • Deaths from hypersensitivity reactions, agranulocytosis, aplastic anemia and other blood dyscrasias, and liver and kidney damage; in hepatic or renal damage or blood dyscrasias use only after critical appraisal.
  • Check blood counts and liver tests before starting, every second week for the first three months, then monthly, and thereafter every three months.
  • Serious infections including fatal sepsis; severe skin and hypersensitivity reactions (DRESS, Stevens-Johnson syndrome, TEN).
  • Oligospermia and infertility in men, apparently reversed after withdrawal.
  • Maintain adequate fluid intake (crystalluria, stones); caution in G6PD deficiency, severe allergy or asthma.

Side effects

  • Most common (in about one-third of patients): anorexia, headache, nausea, vomiting, gastric distress and reversible oligospermia.
  • Less frequent (one in every thirty patients or less): rash, pruritus, urticaria, fever, hemolytic anemia, cyanosis.
  • At 4 g daily or more, or sulfapyridine levels above 50 µg/mL, adverse reactions increase; rare blood dyscrasias such as agranulocytosis or aplastic anemia.

Interactions

  • Reduced absorption of folic acid and digoxin.
  • May interfere with laboratory tests (e.g. false-positive urinary normetanephrine).

Pregnancy and breastfeeding

  • No adequate studies; sulfasalazine inhibits folic acid absorption and metabolism, which may interfere with folic acid supplementation.
  • Sulfapyridine passes into breast milk (about 30 to 60 percent of maternal serum levels); bloody stools or diarrhea have been reported in breastfed infants.

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.

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.

Austria

  • SalazopyrinPfizer Corporation Austria Ges.M.B.H. · 1 register entry

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

Germany

  • AzulfidinePfizer Pharma Gmbh · 2 register entries
  • Sulfasalazin HexalHexal Ag · 1 register entry
  • Sulfasalazin HeylHeyl Chemisch-Pharmazeutische Fabrik Gmbh & Co. Kg · 1 register entry
  • Sulfasalazin MedacMedac Gesellschaft Für Klinische Spezialpräparate Mbh (Wedel) · 1 register entry

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

Turkey

  • KoliletHÜSNÜ ARSAN İLAÇLARI A.Ş. · 3 register entries
  • SalazopyrinPFİZER PFE İLAÇLARI A.Ş. · 1 register entry

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

USA

  • AzulfidinePfizer Laboratories Div Pfizer Inc · 1 register entry
  • Azulfidine EN-tabsPfizer Laboratories Div Pfizer Inc · 1 register entry

Source: U.S. FDA – Drug labels (openFDA/DailyMed), as of 2026-10-29

Brand names in 27 more European countries
Belgium
Salazopyrine Ec
Bulgaria
Сулфасалазин Ен
Croatia
Salazopyrin En, Sulfasalazin En Krka
Cyprus
Salazidin Gr
Czechia
Salazopyrin En, Sulfasalazin K-En
Denmark
Salazopyrin, Sulfasalazin Hexal, Sulfasalazin Medac
Estonia
Salazopyrin En
Finland
Salazopyrin
France
Salazopyrine
Greece
Salopyrine
Hungary
Salazopyrin En
Iceland
Salazopyrin
Ireland
Salazopyrin
Italy
Salazopyrin En
Latvia
Sulfasalazine Krka
Lithuania
Sulfasalazine Krka
Luxembourg
Salazopyrine Ec
Malta
Salazidin, Sulfasalazin Heyl
Netherlands
Salazopyrine E.C., Salazopyrine Zetpil, Sulfasalazine Mylan, Sulfasalazine Sandoz, Sulfasalazine Teva
Norway
Salazopyrin En
Poland
Salazopyrin En, Sulfasalazin En Krka, Sulfasalazin Krka
Portugal
Salazopirina En
Romania
Salazidin, Sulfasalazină En
Slovakia
Sulfasalazin-En
Slovenia
Sulfasalazin Krka
Spain
Salazopyrina
Sweden
Salazopyrin, Sulfasalazin Medac

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

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

Another question about this substance?

Medelix answers clinical questions from guidelines, studies and product information – every claim with its source.

Sources

  1. U.S. Food and Drug Administration. Sulfasalazine (Mylan Pharmaceuticals Inc.) – Prescribing Information, 2026-08-25. DailyMed (NLM), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=48fbc535-a33a-45ee-85ff-9d1ec9b31d9c
  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. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
  5. U.S. FDA – Drug labels (openFDA/DailyMed), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/
  6. Wikidata (CC0): ATC A07EC.

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.