Betamethasone

Betamethasone is a drug from the group of glucocorticoids. It is used to treat a number of conditions including rheumatic conditions such as rheumatoid arthritis and systemic lupus erythematosus, skin conditions such as dermatitis and psoriasis, allergic conditions such as asthma and angioedema, Crohn's disease, cancers such as leukaemia, and in combination with fludrocortisone for adrenal insufficiency. It can be taken by mouth, injected into a muscle, or applied to the skin in the form of a cream or solution. Betamethasone is available by prescription only.

Pharmacodynamics

Betamethasone acts because of its structural similarity to endogenous glucocorticoids. Unbound, it can penetrate the membrane of the cell and then bind with high affinity to intracellular glucocorticoid receptors.

The anti-inflammatory (anti-inflammatory) effect is achieved by interfering with the so-called arachidonic acid metabolism. Betamethasone causes fewer prostaglandins and leukotrienes to be produced at the end of this metabolism. These are significantly involved in the inflammatory process of the human body.

Betamethasone has an anti-allergic effect by preventing the release of histamine and simultaneously reducing the number and activity of certain B and T lymphocytes.

Pharmacokinetics

The absorption and potency of betamethasone is highly dependent on the salt used. By attaching a specific salt, certain properties such as solubility and rate of absorption can be controlled. The metabolism of betamethasone yields 6 metabolites. Metabolic processes include 6β-hydroxylation, 11β-hydroxyl oxidation, and reduction of the C-20 carbonyl group followed by removal of the side chain. Corticosteroids are predominantly excreted in the urine. The half-life of betamethasone is about 10-12 hours.

Side effects

• Euphoria
• Depression
• inhibition of adrenal activity
• Hypertension
• excessive hair growth (hypertrichosis)
• Ecchymosis
• Skin irritations

Prolonged use of this medicine on large areas of skin, broken or rough skin, folds of skin or under airtight dressings may, in rare cases, result in the absorption of enough corticosteroid to cause systemic side effects, such as a decrease in the production of natural hormones by the adrenal glands.

Serious side effects include increased risk of infection, muscle weakness, severe allergic reactions, and psychosis.

Toxicological data

LD50 (mouse, oral): > 4500 mg-kg-1