FML-S
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FML-S (FML-S).
Fluorometholone is a synthetic corticosteroid that binds to the glucocorticoid receptor, modulating gene expression to inhibit phospholipase A2 activity, reduce prostaglandin and leukotriene synthesis, and suppress cytokine production. This results in decreased inflammation, edema, and immune cell infiltration. Sulfacetamide is a sulfonamide antibiotic that competitively inhibits dihydropteroate synthase, blocking folate synthesis and bacterial growth.
| Metabolism | Fluorometholone: Primarily hepatic via CYP3A4. Sulfacetamide: Acetylation in the liver. |
| Excretion | Renal (65-75% as unchanged drug and metabolites), biliary/fecal (15-25%) |
| Half-life | 2.8-3.5 hours; prolonged to 8-12 hours in renal impairment or in neonates |
| Protein binding | 91% bound primarily to albumin |
| Volume of Distribution | 0.8-1.0 L/kg; distributes widely including into aqueous humor |
| Bioavailability | Ophthalmic: <1% systemic absorption; oral: 70-80% |
| Onset of Action | Ophthalmic: 15-30 minutes (topical); systemic: not applicable |
| Duration of Action | 4-6 hours (anti-inflammatory effect); clinical use: 4 times daily dosing |
1-2 drops of 0.1% ophthalmic suspension into the conjunctival sac every 4 hours; may increase to every 2 hours in severe inflammation.
| Dosage form | SUSPENSION/DROPS |
| Renal impairment | No dosage adjustment required for ophthalmic use; negligible systemic absorption. |
| Liver impairment | No dosage adjustment required for ophthalmic use; negligible systemic absorption. |
| Pediatric use | 1 drop of 0.1% ophthalmic suspension into affected eye(s) every 4-6 hours; not recommended for children under 2 years due to potential systemic effects. |
| Geriatric use | Same as adult dosing; monitor intraocular pressure as elderly may be more susceptible to corticosteroid-induced glaucoma. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FML-S (FML-S).
| Breastfeeding | Excreted in breast milk; M/P ratio not determined. Use caution in nursing mothers, especially with high doses or prolonged therapy. Infant may experience adrenal suppression or growth suppression. |
| Teratogenic Risk | Pregnancy Category C. First trimester: potential increased risk of cleft palate; use only if clearly needed. Second and third trimesters: may cause fetal adrenal suppression, intrauterine growth restriction, and hypoglycemia. Prolonged use may lead to premature birth. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to fluorometholone, sulfacetamide, or any component. Epithelial herpes simplex keratitis (dendritic keratitis). Vaccinia, varicella, and other viral diseases of the cornea and conjunctiva. Mycobacterial infections of the eye. Fungal diseases of ocular structures. Untreated purulent ocular infections.
| Precautions | Prolonged use may lead to ocular hypertension/glaucoma, cataract formation, secondary ocular infections, and delayed wound healing. Rebound inflammation upon discontinuation. Monitor intraocular pressure. Not for use in viral, fungal, or mycobacterial infections. Use caution in patients with sulfonamide hypersensitivity; severe reactions (e.g., Stevens-Johnson syndrome) may occur. |
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| Monitor maternal blood glucose, blood pressure, and signs of infection. Assess fetal growth via ultrasound if prolonged therapy. Monitor infant for adrenal insufficiency if used near term. |
| Fertility Effects | No specific human data. In animal studies, high doses may impair fertility; clinical significance unknown. May alter menstrual cycles due to endocrine effects. |