SALAZOPYRIN

Indications

• Ulcerative colitis
• Crohn's disease
• Rheumatoid arthritis
• Ankylosing spondylitis

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines for paediatric patients.

Adults: Refer to the BNF for specific dosing recommendations based on the condition being treated.

Mechanism of action

Sulphasalazine has anti-inflammatory properties which are believed to be due to its metabolite 5-aminosalicylic acid (5-ASA). The drug works by inhibiting the production of inflammatory mediators, including leukotrienes and prostaglandins, thus reducing inflammation in the intestinal mucosa. Additionally, it may affect the immune response by modulating the activity of immune cells.

Pharmacodynamics

Sulphasalazine exhibits both anti-inflammatory and immunosuppressive effects, primarily through its active metabolite. The reduction of inflammation leads to decreased symptoms in conditions like ulcerative colitis and rheumatoid arthritis. Its action on immune cells helps in managing autoimmune conditions by dampening the excessive immune response.

Pharmacokinetics

Sulphasalazine is absorbed in the gastrointestinal tract, with peak plasma concentrations occurring several hours after administration. It undergoes extensive hepatic metabolism, and its metabolites are primarily excreted in the urine. The half-life of sulphasalazine varies widely due to its conversion to 5-ASA and other metabolites. Factors such as age, liver function, and concurrent medications can affect its pharmacokinetics.

Contra-indications

• Hypersensitivity to sulfasalazine or any component of the formulation
• Porphyria
• Severe renal impairment
• Patients with intestinal obstruction or gastrointestinal disorders where bowel rest is required

Adverse effects

• Nausea
• Vomiting
• Headache
• Rash
• Fever
• Bone marrow suppression
• Hepatotoxicity
• Allergic reactions including anaphylaxis

Interactions

• May enhance the effects of anticoagulants such as warfarin
• May reduce the effectiveness of oral contraceptives
• Caution with other drugs that may affect liver function or bone marrow

Precautions

• Monitor liver function and blood counts regularly during treatment
• Use with caution in patients with pre-existing liver or renal disease
• Assess for signs of hypersensitivity reactions
• Consider potential for folate deficiency, supplementation may be required

Pregnancy

Use in pregnancy only if the potential benefit justifies the potential risk to the fetus. Sulfasalazine may cause fetal harm.

Breast-feeding

Sulfasalazine is excreted in breast milk, caution is advised when administering to breastfeeding mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets: 500 mg
• Enteric-coated tablets: 500 mg
• Suspension: 100 mg/5 mL