Sulfasalazine


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Inflammatory bowel disease Initial: 1-2 g 4 times/day till remission. Maintenance: 2 g/day in divided doses. Rheumatoid arthritis As enteric-coated tab: Initial: 500 mg/day for the 1st wk, increase slowly if needed. Max: 3 g/day in 2-4 divided doses. Rectal Inflammatory bowel disease As supp: 0.5-1 g in the morning and night. As enema: 3 g/day at night, retained for at least 1 hr.
Dosage Details
Oral
Inflammatory bowel disease
Adult: Initially, 1-2 g 4 times daily until remission occurs. Maintenance: 2 g/day in divided doses.
Child: ≥2 yr: 40-60 mg/kg/day in divided doses. Maintenance: 20-30 mg/kg/day in divided doses.

Oral
Rheumatoid arthritis
Adult: As enteric-coated tablet: Initially, 500 mg daily for the 1st wk increased by 500 mg every wk. Max: 3 g daily in 2-4 divided doses.
Child: For polyarticular juvenile rheumatoid arthritis: ≥6 yr: As enteric-coated tablet: 30-50 mg/kg/day in 2 divided doses. Begin treatment with 1/4 to 2/3 of expected maintenance dose and increase wkly to reach maintenance dose in 1 mth. Max: 2 g daily.

Rectal
Inflammatory bowel disease
Adult: As suppository: 0.5-1 g in the morning and night, either alone or as an adjunct to oral treatment. As enema: 3 g at night, retained for at least 1 hr.
Renal Impairment
Oral:
Rheumatoid arthritis:
CrCl Dosage
<10ml/min Admin once daily.
10-30 mL/min Admin twice daily.
Inflammatory bowel disease:
CrCl Dosage
<10ml/min Admin once daily.
10-30ml/min Admin twice daily.
Hepatic Impairment
Oral:
Avoid use.
Administration
Should be taken with food. Ensure adequate fluid intake.
Contraindications
Hypersensitivity to sulphonamides or salicylates, porphyria, <2 yr of age, intestinal or urinary obstruction, blood dycrasias, history of leucopenia with gold therapy.
Special Precautions
Hepatic/renal impairment, G6PD deficiency, allergic bronchial asthma, lactation.
Adverse Reactions
Headache, anorexia, nausea, vomiting, diarrhoea, abdominal discomfort, photosensitivity, crystalluria, reversible oligospermia, yellow-orange staining of contact lens, skin, urine and other body fluids, alopoecia.
Potentially Fatal: Severe hypersensitivity reactions, blood dyscrasias, renal and hepatic toxicity, fibrosing alveolitis.
Overdosage
Nausea, vomiting, gastric distress, abdominal pains, drowsiness, convulsions. Gastric lavage or emesis plus catharsis as required. Alkalinize urine. If kidney function is normal, increase fluids. If anuria is present, restrict fluids and salt, and treat accordingly. Catheterization of the ureters may be needed for complete renal blockage by crystals. Hemodialysis may facilitate removal of sulfasalazine and its metabolites. Concentrations of serum sulfapyridine may be used to monitor the progress of recovery.
Drug Interactions
Plasma levels reduced by rifampicin and ethambutol. Interferes with absorption of folic acid. Additive leucopaenia with gold therapy for rheumatoid arthritis. Increased haematological toxicity with azathioprine. Reduced serum levels of digoxin.
Action
Description: Actual mechanism not determined. Sulphasalazine may have direct anti-inflammatory action in the colon. It also systemically interferes with secretion by prostaglandin synthesis inhibition.
Pharmacokinetics:
Absorption: 15% of the dose is absorbed from small intestine, the rest reaches the colon where the azo bond is cleaved by the intestinal flora, producing sulfapyridine and 5-aminosalicylic acid (mesalazine). 60% of the sulfapyridine and 10-30% of the 5-aminosalicylic acid is absorbed from the colon.
Distribution: Following IV admin, vol of distribution is 7.5 L. Sulfasalazine and sulfapyridine crosses the placenta and found in breast milk. Sulfasalazine is extensively protein bound while sulfapyridine is distributed to most body tissues.
Metabolism: Absorbed sulfapyridine undergoes extensive metabolism by acetylation, hydroxylation, and glucuronidation. Slow acetylators are 2-3 times more likely to experience adverse effects from sulfapyridine compared to fast acetylators. Absorbed 5-aminosalicylic acid undergoes acetylation.
Excretion: Via urine,as unchanged sulfasalazine (15%), sulfapyridine and its metabolites (60%), and 5-aminosalicylic acid and its metabolites (20-33%).
Storage
Oral:
Store below 25°C.
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 © 2020 MIMS. All rights reserved. Powered by MIMS.com
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