Products
Sulfasalazine is commercially available as tablets and as dragées with an enteric coating (salazopyrin, salazopyrin EN, some countries: azulfidine, azulfidine EN, or RA). It has been approved in many countries since 1950. EN stands for enteric coated and RA for Rheumatoid Arthritis. EN dragées have a coating to prevent irritation and improve gastric tolerance. They do not disintegrate until they reach the small intestine. The active ingredient was developed in the early 1940s by physician and professor Nanna Svartz at the Karolinska Institute in Sweden in a collaboration with the pharmaceutical company Pharmacia.
Structure and properties
Sulfasalazine (C18H14N4O5S, Mr = 398.4 g/mol) exists as a shiny yellow to brownish yellow fine powder and is practically insoluble in water. It is the prodrug of the two active metabolites mesalazine and sulfapyridine. The aminosalicylate and sulfonamide are linked with an azo group.
Effects
Sulfasalazine (ATC A07EC01) has anti-inflammatory, immunomodulatory, and antibacterial (bacteriostatic) properties. Approximately 20% of the dose is absorbed, with the remainder entering the colon and being metabolized by bacteria. Sulfasalazine is a rare example of a prodrug from which active ingredients are formed. It is referred to as a co-drug or mutual prodrug.
Indications
- Ulcerative colitis
- Crohn’s disease
- Rheumatoid arthritis (chronic polyarthritis)
- Active juvenile idiopathic polyarthritis and spondyloarthropathy with peripheral arthritis in patients 6 years of age and older.
- Active juvenile idiopathic oligoarthritis in children 6 years of age and older.
Dosage
According to the professional information. The drugs are usually taken two to four times a day with food and sufficient liquid. Treatment is started gradually and the dose is adjusted individually. Regular check-ups are required before and during treatment. Because the drug can cause folic acid deficiency, supplementation with folic acid is recommended by various literature sources. There is no corresponding indication in the expert information.
Contraindications
- Hypersensitivity, including to sulfonamides and/or salicylates.
- Acute intermittent porphyria
- Intestinal obstruction
- Severe hepatic and renal insufficiency
- Diseases of the hematopoietic organs
- Glucose-6-phosphate dehydrogenase deficiency
- Children under 2 years
Full precautions can be found in the drug label.
Interactions
Sulfasalazine has a potential for drug-drug interactions. Interactions have been described, for example, with iron, calcium, antibiotics, anion exchangers, vitamin K antagonists, methotrexate, and azathioprine (selection).
Adverse effects
The most common potential adverse effects include:
- Headache
- Gastrointestinal symptoms such as nausea, abdominal pain, loss of appetite, dyspepsia, and stomach discomfort
- Oligospermia and infertility in males, usually reversible two to three months after discontinuation
- Fatigue
Because of its color, sulfasalazine can turn both the skin and urine yellow-orange. Sulfasalazine can cause serious side effects. It can cause myelosuppression, blood count abnormalities, severe infections, severe skin reactions, hepatitis and hypersensitivity reactions. In laboratory animals, sulfasalazine can cause cancer. It is classified as Group 2B (possibly carcinogenic to humans) by the IARC.
