SODIUM SULFACETAMIDE
Clinical safety rating: safe
No significant drug interactions For ophthalmic use only can cause local irritation.
Sulfacetamide is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, thereby blocking the synthesis of folic acid and ultimately nucleic acid synthesis, leading to bacteriostatic activity.
| Metabolism | Sulfacetamide is primarily metabolized via acetylation in the liver, yielding N-acetylsulfacetamide, which is the major inactive metabolite. Minor pathways include glucuronidation. |
| Excretion | Renal: 85-100% unchanged drug via glomerular filtration and tubular secretion. Biliary/fecal: <5%. |
| Half-life | 7-12 hours in normal renal function; prolonged to 20-50 hours in renal impairment. |
| Protein binding | 45-55% primarily to albumin. |
| Volume of Distribution | 0.3-0.5 L/kg, indicating distribution into extracellular fluid. |
| Bioavailability | Topical ophthalmic: minimal systemic absorption (<0.5%). Renal excretion of absorbed fraction. |
| Onset of Action | Topical ophthalmic: within 15-30 minutes. No systemic absorption via intact skin. |
| Duration of Action | Topical ophthalmic: 2-4 hours. Repeated applications required for sustained effect. |
1-2 drops of 10% or 30% solution into conjunctival sac every 2-3 hours during waking hours for 7-10 days.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | Not applicable for ophthalmic use, systemic absorption is minimal. For systemic use: reduce dose or extend interval if CrCl < 50 mL/min. |
| Liver impairment | No adjustment required for ophthalmic use. For systemic use, no specific guidelines; use with caution in severe hepatic impairment. |
| Pediatric use | Children: same as adult dosing, using 10% solution; avoid 30% solution in infants <2 months due to increased risk of kernicterus. |
| Geriatric use | No specific dose adjustment; monitor for local irritation as elderly may have decreased tear production. |
| 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 | Sulfonamides are excreted in breast milk in small amounts. M/P ratio not established. Contraindicated in nursing infants with G6PD deficiency or hyperbilirubinemia. Use caution; avoid if infant is premature, ill, or jaundiced. |
| Teratogenic Risk | Pregnancy Category C. Sulfacetamide crosses the placenta. First trimester: theoretical risk of kernicterus and teratogenicity, but data limited. Second and third trimesters: avoid near term due to risk of kernicterus in newborn; may cause neonatal hyperbilirubinemia if used near delivery. |
■ FDA Black Box Warning
Sulfonamides have been associated with severe adverse reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Fatalities have occurred although rare.
| Common Effects | Stinging |
| Serious Effects |
Hypersensitivity to sulfonamides or any component of the formulation. Contraindicated in infants less than 2 months of age due to risk of kernicterus. Pregnancy (contraindicated at term due to risk of kernicterus in neonate).
| Precautions | Hypersensitivity reactions may occur, including Stevens-Johnson syndrome; discontinue at first sign of rash. Use with caution in patients with impaired renal function. Prolonged use may result in overgrowth of nonsusceptible organisms including fungi. For topical ophthalmic use only; not for injection. Inactivate aminobenzoic acid antagonism. |
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| Fetal Monitoring | Monitor maternal renal and hepatic function, CBC with differential, and bilirubin levels in infant if used near term. Assess for signs of hypersensitivity or kernicterus in neonate. |
| Fertility Effects | No known adverse effects on fertility in animal studies; human data insufficient. |