Dexamethasone
International nonproprietary name (INN)
Dexamethasone
Pharmacotherapeutic group
Drug for eye diseases. Corticosteroid.
Composition
Active ingredient – dexamethasone sodium phosphate (calculated on dry and non-alcoholic basis) 0.1 mg/ml;
Auxiliary substances – boric acid, borax 10-hydrophytic, trilon Б, benzalconic chloride, injection water
Pharmacologicaleffect
Pharmacodynamics
Dexamethasone is synthetic fluoridated glucocorticosteroid of anti-inflammatory, antiallergic, immunosuppressant action, antiexudative and antifibroblastogenic action, practically of mineralcorticosteroid action. Interaction with specific cytoplasmatic receptors and formation of complex penetrating cell nucleus and stimulating synthesis of mRNA; the latter induces protein formation meditating cellular activity, inclusive lipocortin that inhibits phospholipase A2, inhibits liberation of arachidonic acid and biosynthesis of endoperoxides, prostaglandins, leukotriene provoking inflammatory process and allergy. Dexamethasone inhibits the expression of protein genes participating to the development of the inflammatory reactions. It hampers liberation of mediators of inflammation from eosinophils and labrocytes. It inhibits the activity of hyaluronidase, collagenase and protease. It suppresses the action of fibroblasts and collagen formation. It reduces vascular permeability, stabilizes cell membranes, inclusive lysosomal ones, inhibits liberation of cytokines from lymphocytes and macrophages.
Pharmacokinetics
Dexamethasone is absorbed via intact epithelium of cornea into moisture of anterior camera of the eye. The rate of absorption increases under inflammation or injury of mucous membrane. Systemic absorption is low, about 60-80% of dexamethasone in blodd flow is bound with specific protein-carrier transcoritin and albumin, and bound dexamethasoneis of no bioactivity. It easily penetrates histohematogenous barriers, either blood-brain and placental one.
Dexamethasone metabolizes in liver under cytochrome-containing enzymes, and is renal excreted. Anaveragehalf-decompositionperiodis3 h.
Indicationsforusage
Acute and chronic allergic and inflammatory processes: inflammation of the anterior eye segment (conjunctivitis, keratoconjunctivitis, deep keratitis without epithelium damage, iritis, iridocyclitis, episcleritis, scleritis and others), inflammation of posterior eye segment (chorioiditis, optic neuritis), symptomatic uveitis, prevention and treatment of inflammatory state after trauma and eye intervention, thermal burns of eyes in regressive phase.
Administrationanddosage
In adults and children after 12 with acute inflammatory state, in conjunctival sack 1-2 drops 4-5 times a day during 2 days, with diminution of inflammatory symptoms – 3-4 times a day during 4-6 days.
Chronicstate: 1-2 dropstwiceadayduringseveralweeks. Max.period of dosing is 4 weeks.
Postoperative and posttraumatic periods: starting from the 8th day in postoperative period of heterotropia, retina separation, extraction of cataract and from the moment of trauma occurrence 1-2 drops 2-4 times a day during 2-4 weeks; in antiglaucoma filtrating intervention – the day of intervention and the successive day.
In children from 6 to 12 years old with allergy and inflammation 1-2 drops 2-3 times a day during 7-10 days, if necessary, continue after control on the 10th day of the retina state.
Specialindications
Pregnancy and lactation: possible dosing in pregnancy and breast feeding during 7-10 days (only) if the effect is higher than the risk of side effects for mother and fetus.
Remove soft contact lenses before dosing and replace them at least 15 min. later.
Effect on driving and operating risk mechanisms: administration of the drug is nor recommended immediately before driving or operating mechanisms due to possible epiphora after dropping.
Adversereaction
Immediately after dropping possible short-term burning, epiphora, hyperemia of conjunctiva. Possible allergic reaction. Under long treatment (more than 2 weeks) possible hyper- intraocular pressure and cornea perforation (under fascia retinens rostralis), postcapsular cataract (more than 3 weeks treatment).
Contraindications
Hypersensitivity to the drug, virus, fungi infection of the eye, mycobacterial and acute purulent eye diseases, trachoma, glaucoma, damage of cornea epithelium.
Safetymeasures
In ling treatment control cornea and intraocular pressure.
Interactionwithotherdrugs
In long treatment with iodoxuridine possible destruction of cornea epithelium. Under infection possible co-administration of antibacterial medicines.
Overdose
Symptoms: overdose in local administration of dexamethasone may cause side effect aggravation.
Treatment: cancel the drug and administer symptomatic therapy. Nospecificantidote.
Dosageform
1 mlinpolyethylenetubedropper.
5 ml vial of neutral glass.
