HALOSIL CREAM 15GM

Indications

• Psoriasis
• Eczema
• Dermatitis
• Inflammatory skin disorders

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines.

Adults: Apply a thin layer to the affected area once or twice daily. Do not exceed the recommended duration of treatment.

Mechanism of action

The mechanism of action of halobetasol involves binding to the glucocorticoid receptor, leading to decreased vasodilation and permeability of capillaries as well as reduced leukocyte migration to sites of inflammation. This results in inhibition of pro-inflammatory signals and promotion of anti-inflammatory signals. Halobetasol also inhibits phospholipase 2 and prevents neutrophil apoptosis and demargination, thus decreasing the formation of arachidonic acid derivatives. Additionally, it inhibits NF-Kappa B and other inflammatory transcription factors while promoting anti-inflammatory genes like interleukin-10.

Pharmacodynamics

Halobetasol exhibits a moderate duration of action, allowing for once or twice daily applications. The wide therapeutic window of corticosteroids like halobetasol means that patients may require doses significantly higher than the body's natural production. However, patients should be advised about the risks of hypothalamic-pituitary-adrenal axis suppression and increased susceptibility to infections with corticosteroid use.

Pharmacokinetics

Halobetasol, when applied topically, has localized effects with minimal systemic absorption. Its pharmacokinetics may vary based on factors such as skin condition, area of application, and duration of use. The drug's effects peak within hours of application, although the complete therapeutic effects may take longer to manifest due to the underlying mechanisms of action related to gene expression modulation.

Adverse effects

• Skin atrophy
• Striae
• Telangiectasia
• Acne
• Folliculitis
• Hypopigmentation
• Burning
• Itching
• Irritation at the application site

Precautions

• Use with caution in patients with a history of systemic fungal infections
• Consider the potential for adrenal suppression with prolonged use
• Monitor for signs of local infection

Pregnancy

Halobetasol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Caution is advised.

Breast-feeding

Caution is recommended when halobetasol is used during breastfeeding. It is not known if halobetasol is excreted in human milk.

Storage

Store at room temperature, away from direct sunlight and moisture. Keep out of reach of children.

Formulations

• Topical cream
• Topical ointment

Indications

• Acne vulgaris
• Psoriasis
• Warts
• Seborrheic dermatitis
• Dandruff
• Hyperkeratosis

Dosage

Adults: For topical application, salicylic acid is typically applied once or twice daily, depending on the formulation and condition being treated. Specific dosing guidelines should be followed as per the BNF.

Mechanism of action

Salicylic acid exerts its effects by penetrating the skin and exfoliating the stratum corneum through keratolytic action, which helps in the dissolution of keratin and the removal of dead skin cells. This action facilitates the clearance of pores and can reduce acne lesions. Additionally, salicylic acid has anti-inflammatory properties that can help to decrease swelling and redness associated with various skin conditions. The compound is also known to inhibit the activity of enzymes involved in the synthesis of prostaglandins, which are mediators of inflammation.

Pharmacodynamics

The pharmacodynamics of salicylic acid involve its ability to enhance the turnover of skin cells and reduce the cohesiveness of keratinocytes in the stratum corneum. This leads to increased desquamation and a reduction in the formation of microcomedones in acne. Its anti-inflammatory effects are mediated through the inhibition of cyclooxygenase enzymes, leading to decreased production of pro-inflammatory mediators. This contributes to the reduction of inflammation and pain in affected areas.

Pharmacokinetics

Salicylic acid is absorbed percutaneously when applied topically, with systemic absorption increasing with higher concentrations and prolonged application. Once absorbed, it is metabolized predominantly in the liver to various conjugates, which are then excreted by the kidneys. The elimination half-life can vary based on the formulation and concentration used. For topical applications, significant first-pass metabolism may occur, limiting systemic exposure and reducing potential systemic side effects.

Pregnancy

Salicylic acid is classified as pregnancy category C. Its use should be avoided during pregnancy unless the potential benefits outweigh the risks.

Breast-feeding

Salicylic acid is excreted in breast milk, and caution is advised when using it during breastfeeding.

Storage

Store in a cool, dry place away from direct light.

Mechanism of action

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 phospholipase 2 and neutrophil apoptosis and demargination, resulting in decreased formation of arachidonic acid derivatives. They also inhibit NF-Kappa B and other inflammatory transcription factors while promoting 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.

Pharmacodynamics

Corticosteroids bind to the glucocorticoid receptor, inhibiting pro-inflammatory signals, and promoting anti-inflammatory signals. Ulobetasol has a moderate duration of action as it is applied once or twice daily. Corticosteroids have a wide therapeutic window as patients may require doses that are multiples of what the body naturally produces. Patients taking corticosteroids should be counselled regarding the risk of hypothalamic-pituitary-adrenal axis suppression and increased susceptibility to infections.