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 |
| Molecular Weight | 376.5 Da |
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 | Avoid due to risk of cleft palate and growth retardation; fluorinated corticosteroids cross placenta and may cause fetal harm. |
| 2nd trimester | Use only if clearly needed; may cause intrauterine growth restriction and hypothalamic-pituitary-adrenal axis suppression. |
| 3rd trimester | Avoid prolonged use; risk of neonatal adrenal suppression and cataracts. |
Clinical note
Comprehensive clinical and safety monograph for FML-S (FML-S).
| Placental transfer | Fluorometholone is a fluorinated corticosteroid known to cross the placenta. The degree of transfer is significant, especially with topical, nasal, inhaled, or systemic use. Ophthalmic use may result in less systemic exposure but placental transfer occurs due to vascular absorption. |
| Breastfeeding | Corticosteroids are excreted in breast milk; fluorinated compounds like fluorometholone may accumulate. Use minimal effective dose and monitor infant for growth and adrenal effects. Consider alternative non-fluorinated agents if possible. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to fluorometholone or any excipientUntreated bacterial, fungal, viral, or mycobacterial ocular infectionsCorneal epithelial damage (e.g., herpes simplex keratitis)Active ocular herpes simplex
| 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. |
| Food/Dietary | No clinically significant food interactions are expected with ophthalmic use. |
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| Lactation Rating | L3 (Moderately Safe) - limited data suggest risk of adverse effects in nursing infant; benefit should outweigh risk. |
| 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 | 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. |
| Clinical Pearls | FML-S (fluorometholone 0.1% with sulfacetamide sodium 10%) combines a corticosteroid with an antibiotic for ophthalmic use. Reserve for steroid-responsive inflammatory ocular conditions where bacterial infection is present or risk of infection is high. Contraindicated in epithelial herpes simplex keratitis (dendritic keratitis), vaccinia, varicella, mycobacterial infections, and fungal diseases of the eye. Monitor intraocular pressure (IOP) closely; steroid-induced glaucoma may occur after 2-4 weeks of use. Taper dose gradually to avoid rebound inflammation. Do not share the bottle. Discard 28 days after opening. |
| Patient Advice | Shake the bottle well before each use. · Use exactly as prescribed; do not use more often or stop suddenly without consulting your doctor. · Remove contact lenses before instillation and wait at least 15 minutes before reinserting. · Do not touch the dropper tip to any surface to avoid contamination. · Temporary blurred vision may occur; avoid driving or hazardous activities until vision clears. · Report eye pain, vision changes, redness, or discharge immediately. · Do not use for longer than prescribed; prolonged use increases risk of glaucoma, cataracts, and secondary infections. · May cause increased sensitivity to sunlight; wear sunglasses and avoid prolonged sun exposure. |