FLAREX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FLAREX (FLAREX).
Corticosteroid that inhibits phospholipase A2 activity, reducing arachidonic acid release and subsequent production of prostaglandins and leukotrienes, thereby suppressing ocular inflammation.
| Metabolism | Primarily hepatic via CYP3A4; undergoes reduction and conjugation. |
| Excretion | Primarily hepatic metabolism, with inactive metabolites excreted renally (approximately 60-80%) and fecally (20-40%). Less than 5% of unchanged drug appears in urine. |
| Half-life | Terminal elimination half-life is approximately 1-2 hours (mean 1.3 hours) in adults. Due to rapid clearance, accumulation is minimal with topical ophthalmic dosing, but prolonged use may lead to systemic absorption and slightly extended half-life. |
| Protein binding | Approximately 99% bound to plasma proteins, primarily albumin and corticosteroid-binding globulin (transcortin). |
| Volume of Distribution | Apparent volume of distribution (Vd) is approximately 0.3-0.4 L/kg (range 0.2-0.6 L/kg), indicating distribution primarily into extracellular fluid and some tissue binding. |
| Bioavailability | Ophthalmic: Systemic bioavailability is low (approximately 0.5-1%) after topical ocular instillation due to limited ocular absorption and extensive first-pass metabolism in the cornea and nasolacrimal system. No oral formulation. |
| Onset of Action | Ophthalmic: Onset of anti-inflammatory effect occurs within 2-4 hours after instillation. Maximal effect is seen within 24-48 hours. |
| Duration of Action | Ophthalmic: Anti-inflammatory effect persists for 4-6 hours after a single dose. Clinical duration sufficient for twice-daily dosing in most patients. |
1-2 drops in the conjunctival sac every hour during the day and every 2 hours at night initially; after response, reduce to 1 drop every 4 hours, then 1 drop 3-4 times daily. Ophthalmic suspension.
| Dosage form | SUSPENSION/DROPS |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No dosage adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy not established; use only if potential benefit outweighs risk. |
| Geriatric use | No specific dosage adjustment recommended; use lowest effective dose for shortest duration due to increased risk of intraocular pressure elevation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FLAREX (FLAREX).
| Breastfeeding | Systemic corticosteroids are excreted in breast milk, but topical ophthalmic use results in negligible systemic absorption. The M/P ratio is unknown but expected to be very low. Risk to infant is considered minimal; however, caution recommended with prolonged high-dose therapy. |
| Teratogenic Risk | Corticosteroids are associated with increased risk of cleft palate in animal studies. In humans, topically administered ophthalmic corticosteroids have minimal systemic absorption; however, prolonged use may lead to sufficient systemic levels to potentially cause fetal harm. First trimester: theoretical risk of cleft lip/palate. Second and third trimesters: risk of intrauterine growth restriction and adrenal suppression. Use only if clearly needed and at lowest effective dose. |
■ FDA Black Box Warning
None.
| Common Effects | Eye irritation Burning sensation Watery eyes |
| Serious Effects |
["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","Hypersensitivity to any component of the formulation"]
| Precautions | ["May increase intraocular pressure; monitor IOP in patients with glaucoma or with prolonged use","Risk of secondary ocular infection, including fungal and viral infections","Delayed wound healing","Cataract formation with prolonged use","Systemic effects with excessive use, especially in children"] |
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| Fetal Monitoring | Monitor maternal intraocular pressure (IOP) and signs of glaucoma or cataract. In long-term use, assess maternal adrenal function if high doses. Fetal monitoring: ultrasound for growth restriction if prolonged high-dose systemic absorption suspected. |
| Fertility Effects | No specific studies in humans. Animal studies show no impairment of fertility at therapeutic doses. High-dose systemic corticosteroids may disrupt menstrual cycles, but topical ophthalmic use is unlikely to affect fertility. |