Sulfasalazine


Generic Medicine Info
Indications and Dosage
Oral
Crohn's disease
Adult: For active cases, especially in the colon: Initially, 1,000-2,000 mg 4 times daily until remission occurs. May be given with corticosteroids, if necessary. Overnight interval between doses must not exceed 8 hours. Adjust dose according to the severity of the disease, patient response and tolerance. Dosage recommendation may vary among individual products or between countries (refer to detailed product guideline).
Child: ≥2 years For active cases, especially in the colon: 40-60 mg/kg daily in divided doses.

Oral
Rheumatoid arthritis
Adult: In patients who respond inadequately to salicylates or NSAIDs: As enteric-coated or delayed-release tab: Initially, 500 mg daily for the 1st week, then increased by 500 mg every week to 2,000-3,000 mg daily in divided doses according to patient response and tolerance. Max: 3,000 mg daily in 2-4 divided doses. Dosage recommendation may vary among individual products or between countries (refer to detailed product guideline).

Oral
Ulcerative colitis
Adult: Mild to moderate and severe acute attacks: Initially, 1,000-2,000 mg 4 times daily until remission occurs. May be given with corticosteroids, if necessary. Alternatively, initial dose of 3,000-4,000 mg daily in evenly divided doses, or may initiate with 1,000-2,000 mg daily to decrease gastrointestinal intolerance. Overnight interval between doses must not exceed 8 hours. Maintenance of remission: Reduce dose gradually to 2,000 mg daily in divided doses. Adjust dose according to the severity of the disease, patient response and tolerance. Dosage recommendation may vary among individual products or between countries (refer to detailed product guideline).
Child: ≥2 years Acute attacks: 40-60 mg/kg daily in divided doses. Maintenance of remission: 20-30 mg/kg daily in divided doses.

Oral
Polyarticular juvenile rheumatoid arthritis
Child: In patients who responded inadequately to salicylates or other NSAIDs: ≥6 years As enteric-coated or delayed-release tab: 30-50 mg/kg daily in 2 evenly divided doses. Max: 2,000 mg daily. To decrease gastrointestinal intolerance, begin therapy with 1/4 to 1/3 of the planned maintenance dose and increase weekly to reach maintenance dose in 1 month.

Rectal
Crohn's disease
Adult: For active cases: As supp: Initially, 1,000 mg in the morning and at night after defecation. After 3 weeks, dosage may be gradually reduced according to the severity of the disease, patient response and tolerance.

Rectal
Ulcerative colitis
Adult: As supp: Acute attack: Initially, 1,000 mg in the morning and at night after defecation. After 3 weeks, dosage may be gradually reduced according to the severity of the disease, patient response and tolerance. For severe generalised cases of the rectum or recto-sigmoid, or those who respond slowly to oral therapy: 500-1,000 mg in the morning and at night may be given as an adjunct to oral treatment.
Administration
Should be taken with food. Ensure adequate fluid intake.
Contraindications
Hypersensitivity to sulfasalazine or its metabolites, sulfonamides or salicylates. Porphyria, intestinal or urinary obstruction. Children <2 years of age.
Special Precautions
Patient with severe allergies, bronchial asthma, G6PD deficiency, blood dyscrasias; history of recurring or chronic infections, underlying conditions or concomitant treatment that may predispose to infectious complications. Not recommended for use in children with systemic onset juvenile rheumatoid arthritis due to serum sickness-like reaction. Slow acetylators. Renal and hepatic impairment. Children. Pregnancy and lactation.
Adverse Reactions
Significant: Folate deficiency, sulfonamide allergy, gastrointestinal effects (e.g. nausea, vomiting, abdominal discomfort), haemolytic anaemia, crystalluria, kidney stone formation, oligospermia (reversible); yellow or orange skin and urine discolouration.
Blood and lymphatic system disorders: Leucopenia.
Ear and labyrinth disorders: Tinnitus.
Eye disorders: Conjunctival and scleral injection.
Gastrointestinal disorders: Gastric distress, abdominal pain, diarrhoea, dyspepsia, stomatitis, taste disorders.
General disorders and administration site conditions: Fever.
Investigations: Abnormal LFTs.
Metabolism and nutrition disorders: Anorexia.
Musculoskeletal and connective tissue disorders: Arthralgia.
Nervous system disorders: Dizziness, headache.
Psychiatric disorders: Insomnia.
Renal and urinary disorders: Proteinuria.
Respiratory, thoracic and mediastinal disorders: Cough.
Skin and subcutaneous tissue disorders: Pruritus, rash.
Potentially Fatal: Severe hypersensitivity reactions (e.g. Stevens-Johnson syndrome, exfoliative dermatitis, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms), blood dyscrasias (e.g. agranulocytosis, aplastic anaemia, pancytopenia), fibrosing alveolitis, renal damage, hepatic damage (e.g. hepatic necrosis), irreversible neuromuscular and CNS changes, serious infections (e.g. sepsis, pneumonia).
Patient Counseling Information
This drug may cause permanent staining of some extended wear soft contact lenses; remove soft contact lenses during therapy. Ensure adequate fluid intake.
Monitoring Parameters
Monitor CBC with differential and LFTs before treatment initiation, every other week for the 1st 3 months, every month for the 2nd 3 months, then once every 3 months thereafter or as clinically indicated; renal function tests and urinalysis periodically; stool frequency; signs and symptoms of infection, serious skin or systemic hypersensitivity reactions.
Overdosage
Symptoms: Nausea, vomiting, abdominal pain, gastric distress, and drowsiness or convulsions in more advanced cases. Management: Supportive treatment. May perform gastric lavage or emesis and catharsis; alkalinise the urine. If the kidney function is normal, may force fluids. If anuria is present, restrict salt and fluids and treat as appropriate. May perform catheterisation of ureters for complete renal blockage by crystals.
Drug Interactions
May reduce the absorption and serum levels of digoxin and folic acid. May cause bone marrow suppression and leucopenia with mercaptopurine and azathioprine. Increased incidence of gastrointestinal effects, particularly nausea, with methotrexate.
Lab Interference
May cause a false-positive test result with the measurements of urinary normetanephrine by liquid chromatography.
Action
Description: Sulfasalazine is a sulfonamide and generally considered a prodrug since it forms into active 5-aminosalicylic acid (mesalazine) and sulfapyridine. The exact mechanism of 5-aminosalicylic acid is unknown; however, it is thought to modulate local chemical mediators of the inflammatory response and postulated to be a free radical scavenger or an inhibitor of tumour necrosis factor.
Synonym: salazosulfapyridine, sulphasalazine.
Onset: Rheumatoid arthritis: >4 weeks. Ulcerative colitis: >3-4 weeks.
Pharmacokinetics:
Absorption: Approx 10-15% of the oral dose is absorbed from the small intestine (sulfasalazine). Bioavailability: <15% (sulfasalazine); approx 60% (sulfapyridine); approx 10-30% (5-aminosalicylic acid). Time to peak plasma concentration: 3-12 hours (sulfasalazine); approx 10 hours (sulfapyridine, 5-aminosalicylic acid).
Distribution: Crosses the placenta and enters breast milk. Plasma protein binding: >99%, mainly to albumin (sulfasalazine); approx 70% to albumin (sulfapyridine); approx 90% to plasma proteins (acetylsulfapyridine). Volume of distribution: 7.5 ± 1.6 L (sulfasalazine).
Metabolism: Metabolised in the intestine by colonic intestinal flora to sulfapyridine and 5-aminosalicylic acid (mesalazine). Absorbed sulfapyridine is metabolised via acetylation to form acetylsulfapyridine and ring hydroxylation, while 5-aminosalicylic acid undergoes N-acetylation (non-acetylation phenotype dependent route). Rate of metabolism via acetylation is dependent on acetylator phenotype.
Excretion: Mainly via urine (as unchanged drug, conjugates, and acetylated metabolites); faeces (small amounts). Elimination half-life: Sulfasalazine: 7.6 ± 3.4 hours; Sulfapyridine: 14.8 hours (slow acetylators); 10.4 hours (fast acetylators).
Chemical Structure

Chemical Structure Image
Sulfasalazine

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 5339, Sulfasalazine. https://pubchem.ncbi.nlm.nih.gov/compound/Sulfasalazine. Accessed Mar. 26, 2021.

Storage
Store below 25°C.
MIMS Class
Disease-Modifying Anti-Rheumatic Drugs (DMARDs) / GIT Regulators, Antiflatulents & Anti-Inflammatories
ATC Classification
A07EC01 - sulfasalazine ; Belongs to the class of aminosalicylic acid and similar antiinflammatory. Used in the treatment of intestinal inflammation.
References
Anon. Sulfasalazine. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 01/09/2020.

Anon. Sulfasalazine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 01/09/2020.

Buckingham R (ed). Sulfasalazine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/09/2020.

Joint Formulary Committee. Sulfasalazine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/09/2020.

Salazopyrin En-Tabs (Pfizer Limited). MHRA. https://products.mhra.gov.uk. Accessed 01/09/2020.

Salazopyrin Suppositories. MHRA. https://products.mhra.gov.uk. Accessed 01/09/2020.

Sulazine EC (Chelonia Healthcare Limited). MHRA. https://products.mhra.gov.uk. Accessed 01/09/2020.

Sulfasalazine Tablet (Greenstone LLC. DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 01/09/2020.

Sulfasalazine Tablet, Delayed-Release (Greenstone LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 01/09/2020.

Sulfasalazine Tablets (Pfizer Limited). MHRA. https://products.mhra.gov.uk. Accessed 01/09/2020.

Disclaimer: This information is independently developed by MIMS based on Sulfasalazine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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