SULFACETAMIDE SODIUM
Clinical safety rating: safe
No significant drug interactions For ophthalmic use only can cause local irritation.
Competitively inhibits dihydropteroate synthase, blocking folic acid synthesis in susceptible bacteria.
| Metabolism | Primarily hepatic acetylation to inactive metabolites; also undergoes glucuronidation. |
| Excretion | Renal: 85-95% unchanged via glomerular filtration and tubular secretion. Biliary/fecal: <5%. |
| Half-life | 7-12.8 hours (prolonged in renal impairment; requires dosing adjustment in CrCl <50 mL/min). |
| Protein binding | 85-90% bound to serum albumin. |
| Volume of Distribution | 0.2-0.4 L/kg. Indicates distribution primarily in extracellular fluid; low tissue penetration. |
| Bioavailability | Ophthalmic: <0.1% systemic (negligible); Topical (vaginal): <5% systemic. |
| Onset of Action | Ophthalmic (solution): 15-30 minutes; Topical (vaginal cream): within 1 hour. |
| Duration of Action | Ophthalmic: 4-6 hours; Topical: 8-12 hours. Clinical effect persists as long as drug levels maintained above MIC. |
| Molecular Weight | 254.24 |
1-2 drops of 10-30% solution into the conjunctival sac every 2-3 hours initially, tapering as infection resolves. Ointment: 0.5-inch ribbon into conjunctival sac every 3-4 hours and at bedtime.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No systemic dosing adjustment required for ophthalmic use. For rare systemic use, GFR 10-50 mL/min: administer every 12-24 hours; GFR <10 mL/min: administer every 24-48 hours. |
| Liver impairment | No adjustment required for ophthalmic use. For systemic use, Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use. |
| Pediatric use | Children: 1-2 drops of 10-30% solution every 2-3 hours initially. Ointment: 0.25-0.5-inch ribbon every 3-4 hours. Infants and neonates: use with caution; same dosing as children. |
| Geriatric use | No specific dose adjustment required; use lowest effective frequency due to potential for increased systemic absorption from altered ocular surface. |
| 1st trimester | Limited human data; no teratogenicity in animal studies. Use only if clearly needed. |
| 2nd trimester | Limited human data; avoid near term due to risk of kernicterus. |
| 3rd trimester | Avoid near term; sulfonamides can displace bilirubin and increase risk of kernicterus. |
Clinical note
No significant drug interactions For ophthalmic use only can cause local irritation.
| FDA category | Animal |
| Placental transfer | Crosses placenta; fetal serum levels about 50-90% of maternal levels. |
| Breastfeeding | Sulfacetamide is excreted into breast milk in low amounts. Use caution; potential for kernicterus in ill or premature infants. |
■ FDA Black Box Warning
Sulfonamides are contraindicated in patients with a history of hypersensitivity to sulfonamides. Fatalities due to severe reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia) have occurred.
| Common Effects | Stinging |
| Serious Effects |
Hypersensitivity to sulfonamidesSulfonylurea hypersensitivityPorphyria
| Precautions | Hypersensitivity reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis, Blood dyscrasias (agranulocytosis, aplastic anemia, thrombocytopenia), Renal toxicity (crystalluria, oliguria, anuria) – maintain adequate fluid intake, Hepatic necrosis, Ophthalmic use only for topical administration; not for injection, Prolonged use may result in overgrowth of nonsusceptible organisms |
| Food/Dietary |
Loading safety data…
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Sulfacetamide sodium, a sulfonamide antibiotic, crosses the placenta. First trimester: No adequate human studies; animal studies suggest low risk. Second and third trimesters: Risk of kernicterus in neonates if administered near term due to displacement of bilirubin from albumin. Avoid use after 32 weeks gestation. |
| Fetal Monitoring | Monitor maternal renal function and complete blood count during prolonged therapy. In neonates, monitor for signs of jaundice, kernicterus, hemolytic anemia in G6PD deficiency. |
| Fertility Effects | No known adverse effects on human fertility based on limited data. Animal studies show no impairment of fertility at clinical doses. |
| No significant food interactions. However, sulfonamides may cause photosensitivity; avoid excessive sun exposure and use sunscreen. |
| Clinical Pearls | Sulfacetamide sodium is a sulfonamide antibiotic used topically for ocular and dermatological infections. For ophthalmic use, apply to lower conjunctival sac; avoid touching tip to eye or surrounding structures. For dermatological use, it is combined with sulfur for acne vulgaris; apply thin layer to affected areas. Monitor for hypersensitivity reactions, especially in patients allergic to sulfa drugs. Cross-sensitivity with other sulfonamides may occur. Use in infants under 2 months is contraindicated due to risk of kernicterus. |
| Patient Advice | Wash hands before and after application. · For eye drops: shake well, tilt head back, pull down lower lid, and apply drop without touching eye. · For skin preparations: clean affected area before applying; avoid contact with eyes, mouth, or broken skin. · Use exactly as prescribed; do not skip doses or stop early even if symptoms improve. · Inform doctor if you have a sulfa allergy, kidney disease, or are pregnant/breastfeeding. · Possible side effects include stinging, redness, or irritation; report severe reactions like rash, swelling, or difficulty breathing. |