DEXTENZA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DEXTENZA (DEXTENZA).
Dexamethasone is a corticosteroid with glucocorticoid activity that binds to the glucocorticoid receptor, leading to inhibition of inflammatory mediators such as prostaglandins and leukotrienes, and suppression of immune cell migration and activation.
| Metabolism | Primarily hepatic via CYP3A4; dexamethasone is a substrate of CYP3A4 and induces CYP3A4 and P-glycoprotein. |
| Excretion | Dextenza (dexamethasone ophthalmic insert) is administered intracanalicularly; systemic absorption is minimal. Following release into the tear film, the drug is primarily eliminated via nasolacrimal drainage and subsequent gastrointestinal absorption with hepatic metabolism. Renal excretion accounts for <5% of the dose as unchanged drug; biliary/fecal elimination is negligible. |
| Half-life | The terminal elimination half-life of dexamethasone from plasma after systemic absorption is approximately 3-4 hours. However, Dextenza provides sustained local delivery to the ocular surface; the insert releases dexamethasone over 30 days, with therapeutic levels maintained throughout. |
| Protein binding | Dexamethasone is approximately 77-80% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | The apparent volume of distribution (Vd) for dexamethasone is approximately 0.75 L/kg, indicating distribution into total body water and tissues. Locally, the insert concentrates drug at the ocular surface. |
| Bioavailability | Bioavailability after intracanalicular administration is high at the target site (ocular surface) due to direct release. Systemic bioavailability is negligible (less than 5%), as the drug is primarily retained locally and eliminated via nasolacrimal drainage. |
| Onset of Action | After intracanalicular placement, onset of clinical effect (reduction of ocular inflammation and pain) is observed within 24-48 hours as dexamethasone is released into the tear film. |
| Duration of Action | Each insert delivers dexamethasone continuously for up to 30 days, providing sustained anti-inflammatory and analgesic effects. The insert dissolves over time, with complete resorption typically occurring within 30 days. |
Insert 0.4 mg intracanalicularly (into the lacrimal punctum) as a single dose; releases dexamethasone over 30 days.
| Dosage form | INSERT |
| Renal impairment | No dose adjustment required based on renal function. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic impairment. |
| Pediatric use | Safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dose adjustment; use with consideration for age-related ocular conditions. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DEXTENZA (DEXTENZA).
| Breastfeeding | Systemic dexamethasone is excreted into breast milk. Dextenza has minimal systemic absorption, however, due to potential for adverse effects in the infant, caution should be exercised. M/P ratio not established for this formulation. |
| Teratogenic Risk | Corticosteroids are known teratogens in animal studies. Dextenza (dexamethasone ophthalmic insert) has limited systemic absorption, but fetal risk cannot be completely excluded. Use during pregnancy only if potential benefit justifies potential risk to the fetus. Preclinical data suggest increased risk of cleft palate and intrauterine growth restriction with systemic corticosteroids in pregnancy. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to dexamethasone or any component of the formulation.","Active ocular infections (e.g., herpes simplex keratitis, fungal, bacterial, or mycobacterial infections)."]
| Precautions | ["May increase intraocular pressure; monitor in patients with glaucoma.","May delay wound healing.","May increase risk of secondary ocular infections, including fungal infections.","Use with caution in patients with corneal thinning or perforation.","Systemic effects possible with prolonged use."] |
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| Fetal Monitoring | Monitor intraocular pressure if used for more than 10 days. In pregnancy, routine prenatal care, fundal height measurements, and fetal growth assessment via ultrasound if prolonged use. Monitor for signs of corticosteroid adverse effects such as elevated blood pressure, blood glucose, and weight gain. |
| Fertility Effects | No specific fertility studies with Dextenza. Systemic corticosteroids may affect ovulation and menstrual cycle regularity. Corticosteroids may suppress hypothalamic-pituitary-adrenal axis. Use with caution in women attempting conception. |