Name of the medicinal product:
Betnovate Cream
Qualitative and quantitative composition:
- Betamethasone Valerate BP 0.122% W/W;
Excipients with known effect:
- Chlorocresol;
- Cetostearyl alcohol.
Therapeutic indications:
Betamethasone valerate is a potent topical corticosteroid indicated for adults, elderly and children over 1 year for the relief of the inflammatory and pruritic manifestations of steroid responsive dermatoses. These include the following:
* Atopic dermatitis (including infantile atopic dermatitis);
* Nummular dermatitis (discoid eczema);
* Prurigo nodularis;
* Psoriasis (excluding widespread plaque psoriasis);
* Lichen simplex chronicus (neurodermatitis) and lichen planus;
* Seborrhoeic dermatitis;
* Irritant or allergic contact dermatitis;
* Discoid lupus erythematosus;
* Adjunct to systemic steroid therapy in generalised erythroderma;
* Insect bite reactions.
Route of administration: Cutaneous
Creams are especially appropriate for moist or weeping surfaces.
Apply thinly and gently rub in using only enough to cover the entire affected area once or twice daily for up to 4 weeks until improvement occurs, then reduce the frequency of application or change the treatment to a less potent preparation.
Allow adequate time for absorption after each application before applying an emollient.
In the more resistant lesions, such as the thickened plaques of psoriasis on elbows and knees, the effect of betamethasone valerate can be enhanced, if necessary, by occluding the treatment area with polythene film. Overnight occlusion only is usually adequate to bring about a satisfactory response in such lesions; thereafter, improvement can usually be maintained by regular application without occlusion.
If the condition worsens or does not improve within 2-4 weeks, treatment and diagnosis should be re-evaluated.
Therapy with betamethasone valerate should be gradually discontinued once control is achieved and an emollient continued as maintenance therapy.
Rebound of pre-existing dermatoses can occur with abrupt discontinuation of betamethasone valerate.
Mechanism of action
Topical corticosteroids act as anti-inflammatory agents via multiple mechanisms to inhibit late phase allergic reactions including decreasing the density of mast cells, decreasing chemotaxis and activation of eosinophils, decreasing cytokine production by lymphocytes, monocytes, mast cells and eosinophils, and inhibiting the metabolism of arachidonic acid.
Pharmacodynamic effects
Topical corticosteroids have anti-inflammatory, antipruritic, and vasoconstrictive properties.
Pharmacokinetic properties
Absorption
Topical corticosteroids can be systemically absorbed from intact healthy skin. The extent of percutaneous absorption of topical corticosteroids is determined by many factors, including the vehicle and the integrity of the epidermal barrier. Occlusion, inflammation and/or other disease processes in the skin may also increase percutaneous absorption.
Distribution
The use of pharmacodynamic endpoints for assessing the systemic exposure of topical corticosteroids is necessary because circulating levels are well below the level of detection.
Metabolism
Once absorbed through the skin, topical corticosteroids are handled through pharmacokinetic pathways similar to systemically administered corticosteroids. They are metabolised, primarily in the liver.
Elimination
Topical corticosteroids are excreted by the kidneys. In addition, some corticosteroids and their metabolites are also excreted in the bile.
Special warnings and precautions for use
Betamethasone valerate should be used with caution in patients with a history of local hypersensitivity to other corticosteroids. Local hypersensitivity reactions may resemble symptoms of the condition under treatment.
Manifestations of hypercortisolism (Cushing's syndrome) and reversible hypothalamic-pituitary-adrenal (HPA) axis suppression, leading to glucocorticosteroid insufficiency, can occur in some individuals as a result of increased systemic absorption of topical steroids. If either of the above are observed, withdraw the drug gradually by reducing the frequency of application, or by substituting a less potent corticosteroid. Abrupt withdrawal of treatment may result in glucocorticosteroid insufficiency
