RETISERT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RETISERT (RETISERT).
Fluocinolone acetonide is a corticosteroid that binds to glucocorticoid receptors, inhibiting inflammatory mediators such as prostaglandins and leukotrienes, and suppressing immune response.
| Metabolism | Primarily hepatic via CYP3A4; undergoes reduction, hydroxylation, and glucuronidation. |
| Excretion | Primarily hepatic metabolism; renal excretion as metabolites (approximately 50% within 40 days, with ~20% unchanged). Fecal excretion accounts for ~30%. |
| Half-life | Terminal half-life is approximately 110 days (range 50-150 days) in the systemic circulation following intravitreal implantation, reflecting slow release from the implant. |
| Protein binding | Approximately 99% bound primarily to albumin and corticosteroid-binding globulin (CBG). |
| Volume of Distribution | Fluocinolone acetonide exhibits a large apparent volume of distribution (Vd approximately 6.2 L/kg after IV administration), indicating extensive tissue distribution. |
| Bioavailability | Intravitreal implant: 100% (direct delivery to vitreous). Oral: Not applicable; systemic bioavailability negligible due to extensive first-pass metabolism. |
| Onset of Action | Intravitreal implant: Clinical effect (reduction in inflammation) typically observed within 2-4 weeks post-implantation. |
| Duration of Action | The implant provides sustained release for up to 30 months (2.5 years) in the vitreous cavity, with therapeutic effects lasting throughout the implant's lifespan. |
| Molecular Weight | 452.5 |
Intravitreal implant containing 0.59 mg fluocinolone acetonide; one implant inserted into the vitreous cavity via pars plana injection; release fluocinolone for up to 30 months; single dose per eye.
| Dosage form | IMPLANT |
| Renal impairment | No specific GFR-based dose adjustment required; renal impairment does not significantly affect systemic exposure due to local administration. |
| Liver impairment | No specific Child-Pugh-based dose adjustment required; hepatic impairment is unlikely to alter local drug action; use caution in severe hepatic disease due to corticosteroid systemic effects. |
| Pediatric use | Not approved in pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dose adjustment; monitor for intraocular pressure elevation and cataract formation, which may be more frequent in elderly; use same dosing as adults. |
| 1st trimester | Fluocinolone acetonide intravitreal implant is not absorbed systemically; no fetal risk expected. Use only if benefit clearly outweighs risk. |
| 2nd trimester | Same as T1; no systemic absorption. Category C (animal studies show risk, no human studies). |
| 3rd trimester | Same as T1; no systemic absorption. Category C. |
Clinical note
Comprehensive clinical and safety monograph for RETISERT (RETISERT).
| Placental transfer | Minimal to no expected placental transfer due to intravitreal route and negligible systemic absorption. Low molecular weight (452.5 Da) could theoretically cross, but lack of systemic levels makes transfer unlikely. |
| Breastfeeding | Systemic absorption is negligible after intravitreal administration. Excretion into breast milk is unlikely. Use with caution, but considered compatible with breastfeeding. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to fluocinolone acetonide or any component of the implantActive ocular or periocular infections (e.g., viral, fungal, bacterial)Glaucoma with cup-to-disc ratio >0.8Aphakic eyes with torn posterior capsule
| Precautions | Increased intraocular pressure (IOP) and glaucoma, Cataract formation, Endophthalmitis, Retinal detachment, Mydriasis, Delayed wound healing |
| Food/Dietary | No specific food interactions. Maintain normal diet unless otherwise instructed by physician. |
| Clinical Pearls |
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| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | FDA Pregnancy Category C. In animal studies, fluocinolone acetonide (the active ingredient in RETISERT) has been shown to be teratogenic at subcutaneous doses of 0.1 mg/kg/day in rabbits and 0.05 mg/kg/day in rats, causing fetal abnormalities including cleft palate and umbilical hernia. There are no adequate and well-controlled studies in pregnant women. The intravitreal implant results in minimal systemic exposure; however, theoretical risk exists. Use during pregnancy only if potential benefit justifies the potential risk to the fetus. |
| Fetal Monitoring | Monitor intraocular pressure regularly (e.g., at 1 week, 1 month, and then every 3 months post-implant). Assess for endophthalmitis, retinal detachment, and cataract formation. In pregnant women, consider fetal ultrasound monitoring if systemic exposure is a concern, though exposure is minimal. |
| Fertility Effects | In animal studies, fluocinolone acetonide at subcutaneous doses up to 0.5 mg/kg/day in rats did not impair fertility. No specific human data are available for intravitreal use. The implant's local action and low systemic levels suggest minimal impact on fertility. |
| RETISERT (fluocinolone acetonide intravitreal implant) is indicated for chronic non-infectious uveitis affecting the posterior segment. Monitor for elevated intraocular pressure (IOP) and cataracts; patients often require additional IOP-lowering therapy. Implant releases corticosteroid over ~30 months; do not use in eyes with active or suspected infections. Avoid in patients with glaucoma that is not adequately controlled. |
| Patient Advice | This implant slowly releases steroid inside your eye for about 2.5 years. · You will need regular eye exams to check eye pressure and for cataracts. · Report any eye pain, redness, or vision changes immediately. · Do not rub or press on the eye; avoid activities that could hit the eye. · Inform all doctors you have this implant before any eye procedures. · You may need additional eye drops or surgery for increased eye pressure or cataracts. |