SULTRIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SULTRIN (SULTRIN).
Sultrin (sulfanilamide, sulfathiazole, sulfacetamide) is a triple sulfonamide combination that acts as a bacteriostatic agent. It inhibits bacterial folic acid synthesis by competing with para-aminobenzoic acid (PABA) for the active site of dihydropteroate synthase, thereby blocking the conversion of PABA to dihydrofolic acid. This disrupts nucleic acid synthesis in susceptible bacteria.
| Metabolism | Sulfonamides are primarily metabolized in the liver via acetylation (N-acetyltransferase) and glucuronidation. The acetylated metabolites are inactive but may crystallize in urine at high concentrations. |
| Excretion | Renal: ~70% unchanged; biliary/fecal: ~30% as metabolites |
| Half-life | Terminal half-life 8-12 hours; requires dose adjustment in renal impairment (CrCl <30 mL/min) |
| Protein binding | 65% bound to albumin |
| Volume of Distribution | 0.3 L/kg; indicates distribution primarily into extracellular fluid |
| Bioavailability | Oral: 90% (first-pass metabolism minimal); IM: 100% |
| Onset of Action | Oral: 30-60 minutes; intravenous: immediate |
| Duration of Action | Therapeutic effect persists 6-8 hours post-dose; residual effect may last up to 12 hours |
| Molecular Weight | 255.32 |
Intravaginal administration: one applicatorful (approximately 5 g) of Sultrin Triple Sulfa Cream (containing sulfathiazole, sulfacetamide, and sulfabenzamide) intravaginally once or twice daily for 4 to 7 days. Oral: Not applicable.
| Dosage form | CREAM |
| Renal impairment | Contraindicated in patients with significant renal impairment (e.g., GFR <30 mL/min/1.73 m²) due to risk of sulfonamide accumulation and toxicity. No specific dose adjustment guidelines available; use is not recommended. |
| Liver impairment | No specific guidelines for Child-Pugh classification. Use with caution in severe hepatic impairment due to potential sulfonamide metabolism alterations. Monitor for signs of toxicity. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established. Not recommended for use in children. |
| Geriatric use | Use with caution in elderly patients due to age-related renal function decline. Monitor renal function and for adverse reactions; consider alternative therapy if renal impairment is present. |
| 1st trimester | Avoid use due to known teratogenic effects; sulfonamides may cause kernicterus in newborns and have been associated with congenital malformations in animal studies. |
| 2nd trimester | Use only if clearly needed; sulfonamides compete with bilirubin for albumin binding, potentially increasing risk of kernicterus if used near term. |
| 3rd trimester | Contraindicated near term (after 37 weeks) due to risk of kernicterus in the newborn; also avoid during labor and delivery. |
Clinical note
Comprehensive clinical and safety monograph for SULTRIN (SULTRIN).
| Placental transfer | Sulfonamides (including sulfathiazole) readily cross the placenta, achieving fetal serum levels of 50-90% of maternal levels. |
| Breastfeeding | Sulfonamides are excreted into breast milk in small amounts. In infants with glucose-6-phosphate dehydrogenase deficiency, sulfonamides may cause hemolytic anemia. Use with caution in breastfeeding mothers, especially if the infant is preterm, hyperbilirubinemic, or has G6PD deficiency. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to sulfonamides or any component of the formulationInfants less than 2 months of age (except for treatment of congenital toxoplasmosis)Pregnancy at term (after 37 weeks) and during labor and deliveryBreastfeeding in infants with hyperbilirubinemia or G6PD deficiencyConcomitant use with methenamine (risk of crystalluria)
| Precautions | Risk of severe hypersensitivity reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis, Hematologic toxicity: agranulocytosis, aplastic anemia (especially with prolonged use), Renal toxicity: crystalluria and renal tubular obstruction, particularly in dehydrated patients or those with renal impairment, Hepatic impairment: risk of hepatotoxicity and hyperbilirubinemia, Prolonged use may lead to superinfection with resistant organisms, Avoid use during pregnancy near term due to risk of kernicterus in the newborn, Cross-sensitivity with other sulfonamides and thiazide diuretics |
| Food/Dietary | No clinically significant food interactions. No dietary restrictions required. |
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| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Sultrin (sulfanilamide) is a sulfonamide antimicrobial. First trimester: Crosses placenta, potential for teratogenicity (cleft palate, cardiovascular defects) based on animal studies; human data insufficient. Second and third trimesters: Risk of kernicterus in neonates due to bilirubin displacement if administered near term. Contraindicated after 32 weeks gestation. |
| Fetal Monitoring | Monitor maternal CBC, renal function, and liver function tests. Fetal ultrasound for anomalies if used in first trimester. Neonatal bilirubin levels and signs of kernicterus if used near term. |
| Fertility Effects | No specific data on fertility impairment in humans. Sulfonamides may affect spermatogenesis in animal studies, but clinical relevance unclear. |
| Clinical Pearls | SULTRIN (sulfacetamide sodium 10%, sulfur 5%) is a topical sulfonamide with keratolytic activity. Effective for acne vulgaris and seborrheic dermatitis. Avoid use in patients with known sulfonamide hypersensitivity. Reassess if no improvement after 8-12 weeks. Use caution in renal impairment due to potential systemic absorption. May stain clothing and jewelry. |
| Patient Advice | Apply a thin layer to affected areas once or twice daily as directed. · Avoid contact with eyes, mouth, and mucous membranes. · May cause temporary stinging or burning upon application. · Do not use if allergic to sulfa drugs or sulfur. · Discontinue and inform doctor if skin rash or irritation develops. · Antibacterial activity may be reduced by concomitant use of other topical products containing heavy metals (e.g., mercury, silver). |