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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions For ophthalmic use only can cause local irritation.
| FDA category | Animal |
| Breastfeeding | Sulfacetamide is excreted into breast milk. M/P ratio is approximately 0.23. Low oral bioavailability in infants makes systemic absorption unlikely. However, risk of kernicterus exists in premature or hyperbilirubinemic infants. Use with caution. |
| 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. |
■ 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 sulfonamides or any component of the formulation","Infants less than 2 months of age (except for congenital toxoplasmosis)","Pregnancy (near term) due to risk of kernicterus in neonates"]
| 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"] |
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| 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. |