FML
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FML (FML).
Agonist at glucocorticoid receptors, leading to inhibition of phospholipase A2 via annexin-1 induction, reducing prostaglandin and leukotriene synthesis; also suppresses cytokine production and inflammatory cell migration.
| Metabolism | Primarily hepatic via CYP3A4; undergoes reduction and conjugation to inactive metabolites. |
| Excretion | FML (fluorometholone) is primarily metabolized in the liver, with metabolites excreted renally. Approximately 70-80% of the dose is eliminated in urine as metabolites, with less than 5% as unchanged drug. Fecal excretion accounts for about 10%. |
| Half-life | The terminal elimination half-life of fluorometholone is approximately 1.5 hours in plasma. Clinically, this short half-life allows for multiple daily dosing; however, ocular administration results in sustained local effects due to corneal binding. |
| Protein binding | Plasma protein binding of fluorometholone is approximately 79-85%, primarily to albumin and corticosteroid-binding globulin. |
| Volume of Distribution | The volume of distribution (Vd) is approximately 1.0 L/kg, indicating extensive tissue distribution. This is consistent with its lipophilic nature, allowing penetration into ocular tissues. |
| Bioavailability | Ophthalmic suspension: Systemic bioavailability is extremely low (less than 1%) due to extensive first-pass metabolism in the eye and systemic circulation. Oral bioavailability is not clinically relevant as the drug is only administered topically. |
| Onset of Action | Ophthalmic suspension: Onset of action is within 1-2 hours after topical application, with maximal effect typically seen at 4-8 hours. |
| Duration of Action | Ophthalmic: Duration of anti-inflammatory effect is approximately 8-24 hours, depending on dosing frequency (typically 2-4 times daily). Systemic effects are limited due to low bioavailability. |
| Molecular Weight | 376.47 |
Fluorometholone ophthalmic suspension 0.1%: Instill 1 drop into conjunctival sac 2-4 times daily. In severe conditions, may increase to 1 drop every hour initially.
| Dosage form | SUSPENSION/DROPS |
| Renal impairment | No adjustment required. |
| Liver impairment | No adjustment required. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established; use only if clearly needed. |
| Geriatric use | No specific dosage adjustment; use lowest effective dose for shortest duration due to increased risk of intraocular pressure elevation. |
| 1st trimester | Topical ocular use generally considered safe; systemic absorption minimal. No evidence of teratogenicity in animal studies, but caution advised. |
| 2nd trimester | Safe for topical ocular use; limited systemic absorption. Monitor for potential increase in intraocular pressure. |
| 3rd trimester | Safe for short-term topical ocular use; avoid prolonged high-dose use due to possible fetal adrenal suppression from systemic absorption. |
Clinical note
Comprehensive clinical and safety monograph for FML (FML).
| Placental transfer | Fluorometholone crosses the placenta; systemic absorption after topical ocular use is minimal, but high doses or prolonged therapy may lead to detectable levels in fetal circulation. |
| Breastfeeding | Topical ocular administration results in negligible systemic absorption; unlikely to affect breastfed infant. However, if high doses or prolonged treatment required, consider using alternate therapy or monitor infant for signs of adrenal suppression. |
■ FDA Black Box Warning
None
| Common Effects | Eye irritation Burning sensation Watery eyes |
| Serious Effects |
Hypersensitivity to fluorometholone or any componentCorneal epithelial herpes simplex (dendritic keratitis)Fungal diseases of ocular structuresUntreated purulent eye infectionsVaccinia, varicella, and other viral infections of cornea and conjunctiva
| Precautions | Prolonged use may cause elevated intraocular pressure, glaucoma, cataract formation, and secondary ocular infections., May suppress immune response, increasing risk of fungal, viral, or bacterial infections., Use with caution in patients with corneal thinning or epithelial defects., Systemic absorption may occur with extensive topical use., Not for use in patients with untreated ocular infections. |
| Food/Dietary |
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| Lactation Rating | L1 (Safer) |
| Teratogenic Risk | Pregnancy Category C. In first trimester, possible increased risk of oral clefts (case-control studies inconsistent). Second/third trimester: chronic use may cause intrauterine growth restriction, adrenal suppression in fetus; avoid prolonged high-dose use. Systemic absorption from topical ophthalmic administration is low but can accumulate with extensive use. |
| Fetal Monitoring | Monitor for intrauterine growth restriction (serial ultrasound if chronic use). Assess maternal adrenal suppression (ACTH stimulation test if high-dose systemic exposure). Monitor infant for signs of adrenal suppression if maternal long-term therapy near term. |
| Fertility Effects | No specific human data. In animal studies, corticosteroids may impair fertility at high doses (e.g., delayed ovulation, reduced implantation); relevance to ophthalmic use is minimal due to low systemic absorption. |
| No significant food interactions. Avoid alcohol as it may increase absorption and systemic side effects. |
| Clinical Pearls | FML (fluorometholone) is a corticosteroid with lower intraocular pressure (IOP) elevation risk than prednisolone, making it preferred for long-term use in steroid responders or glaucoma patients. Shake suspension well before use. Discard after 4 weeks of opening due to contamination risk. Do not use for corneal epithelial defects due to delayed healing. Monitor for secondary infections and cataracts with prolonged use. |
| Patient Advice | Shake the bottle well before each use. · Avoid touching the dropper tip to any surface to prevent contamination. · Do not use while wearing contact lenses; wait at least 15 minutes after instillation before inserting lenses. · Report any eye pain, vision changes, or lack of improvement to your doctor. · Do not stop abruptly if using for a chronic condition; taper as directed. |