Betamethasone phosphate

Uses

Short-term treatment of steroid responsive in inflammatory conditions of the eye after clinical exclusion of bacterial, viral or fungal infections. Non-infected inflammatory conditions of the ear or nose.

Betamethasone phosphate is also used to associated treatment for these conditions: Acute Gouty Arthritis, Allergic Conditions, Alopecia Areata (AA), Dermatological Disease, Discoid Lupus Erythematosus (DLE), Endocrine Disorders, Epicondylitis, Gastrointestinal Diseases, Haematological disorders, Keloid Scars, Kidney Diseases, Lichen Planus (LP), Lichen simplex chronicus, Necrobiosis lipoidica diabeticorum, Neoplastic Disease, Nervous System Disorders, Ophthalmic Diseases, Psoriatic plaque, Respiratory Diseases, Rheumatism, Rheumatoid Arthritis, Acute Bursitis, Acute nonspecific tenosynovitis, Cystic tumors of aponeurosis, Cystic tumors of tendon, Localized Hypertrophic, Inflammatory, Infiltrated granuloma annulare lesions, Subacute Bursitis, Synovitis of osteoarthritis

How Betamethasone phosphate works

Betamethasone phosphate is a soluble ester prodrug of betamethasone. Betamethasone is rapidly de-esterified, allowing betamethasone to act as an agonist of the glucocorticoid receptor. The short term effects of corticosteroids are decreased vasodilation and permeability of capillaries, as well as decreased leukocyte migration to sites of inflammation. Corticosteroids binding to the glucocorticoid receptor mediates changes in gene expression that lead to multiple downstream effects over hours to days.

Glucocorticoids inhibit neutrophil apoptosis and demargination; they inhibit phospholipase A2, which decreases the formation of arachidonic acid derivatives; they inhibit NF-Kappa B and other inflammatory transcription factors; they promote anti-inflammatory genes like interleukin-10.

Lower doses of corticosteroids provide an anti-inflammatory effect, while higher doses are immunosuppressive. High doses of glucocorticoids for an extended period bind to the mineralocorticoid receptor, raising sodium levels and decreasing potassium levels.

Dosage

Betamethasone phosphate dosage

Eye: 1 or 2 drops to each affected eye every 1 or 2 hours until control is achieved, then the frequency may be reduced.
Ear: 2 or 3 drops to each affected ear every 2 or 3 hours until control is achieved, then the frequency may be reduced.
Nose: 2 or 3 drops instilled into each nostril 2 or 3 times daily.

Side Effects

Hypersensitivity reactions may occur leading to irritation, burning, stinging, itching and dermatitis. Topical corticosteroid use may result in corneal ulceration, increased intraocular pressure leading to optic nerve damage, reduced visual acuity. Intensive or prolonged use of topical corticosteroids may lead to formation of posterior subcapsular cataracts. In those diseases causing thinning of the cornea or sclera, corticosteroid therapy may result in thinning of the globe leading to perforation. Mydriasis, ptosis and epithelial punctate keratitis have also been reported following ophthalmic use of corticosteroids.

Toxicity

Patients experiencing an acute overdose should be treated with symptomatic and supportive treatment. Chronic overdoses where patients require continued therapy can be treated through temporary dose reduction or alternate day treatment.

The oral, intraperitoneal, and intravenous LD₅₀ values in rats are 1877 mg/kg, 1179 mg/kg, and 1276 mg/kg, respectively.

Precaution

Topical corticosteroids should never be given for an undiagnosed red eye. Ophthalmic treatment with corticosteroid preparations should not be repeated or prolonged without regular review to exclude raised intraocular pressure, cataract formation or unsuspected infections.

Interaction

Specific drug interaction studies have not been conducted.

Food Interaction

Volume of Distribution

The volume of distribution of betamethasone in an intramuscular injection of 3mg betamethasone acetate and 3mg betamethasone phosphate is 226.00 ± 61.64 L.

Elimination Route

An intramuscular injection of 3mg betamethasone acetate and 3mg betametasone phosphate reaches a betamethasone C_max 33.21 ± 8.71 ng/mL, with a T_max of 1.56 ± 1.32 h, and an AUC of 506.95 ± 125.03 ng*h/mL.

Half Life

The half life of betamethasone in an intramuscular injection of 3mg betamethasone acetate and 3mg betamethasone phosphate is 12.47 ± 1.91 h.

Clearance

The clearance of betamethasone in an intramuscular injection of 3mg betamethasone acetate and 3mg betamethasone phosphate is 12.62 ± 3.45 L/h.

Elimination Route

Corticosteroids are eliminated predominantly in the urine.

Pregnancy & Breastfeeding use

There are no adequate and well controlled studies for pregnant woman. It should not be used extensively in pregnant woman. There is no information available whether it is secreted in the milk or not.

Acute Overdose

Long-term intensive topical use may lead to systemic effects.

Storage Condition

This should be protected from light, store below 25°C. Keep out of reach of children. Do not use more than 4 weeks after opening.

Innovators Monograph

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