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ANTIINFECTIVES FOR SYSTEMIC USE › ANTIBACTERIALS FOR SYSTEMIC USE › SULFONAMIDES AND TRIMETHOPRIM › Short-acting sulfonamides
sulfathiazole
J01EB07
Forms & Strengths
- Topical cream/ointment: 5%
- Vaginal cream: 3.42% to 10%
- Oral tablets: 500 mg (historical/largely obsolete)
Adult Dosing
- Topical: Apply a small amount to affected areas 1 to 4 times daily
- Vaginal: One applicatorful intravaginally once or twice daily
- Oral (historical): 2 to 4 g initially, then 0.5 to 1 g every 4 to 6 hours
Pediatric Dosing
- Topical: Apply sparingly to affected areas 1 to 2 times daily in children > 2 months
- Oral: Not recommended due to high toxicity profile and availability of safer alternatives
Indications
- Treatment of minor skin infections caused by susceptible organisms (topical)
- Adjunctive treatment of bacterial vaginosis (vaginal)
- Historical use for systemic bacterial infections (largely replaced by safer antibiotics)
Mechanism of Action
- Competitive inhibitor of dihydropteroate synthase
- Blocks bacterial synthesis of dihydrofolic acid
- Inhibits folic acid synthesis required for bacterial purine and pyrimidine production
Contraindications
- Known hypersensitivity to sulfonamides
- Infants under 2 months of age due to risk of kernicterus
- Porphyria
- Severe hepatic impairment or renal failure
Adverse Reactions
- Hypersensitivity reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis
- Contact dermatitis and local irritation (topical use)
- Hematologic toxicities including hemolytic anemia, agranulocytosis, and aplastic anemia
- Photosensitivity
Drug Interactions
- Enhances effect of oral anticoagulants (e.g., warfarin) by displacement from protein binding sites
- Increases risk of bone marrow suppression when co-administered with myelosuppressive agents
- May decrease efficacy of bacteriostatic antibiotics
- May potentiate hypoglycemic effects of sulfonylureas
Curated Content: Needs Vetting Before Put to Clinical Use