ZOFU DUSTING POWDER

Indications

• Chafing
• Diaper rash
• Fungal infections
• Irritation due to moisture

Dosage

Children: Apply a thin layer to the affected area as needed. Refer to specific product instructions for optimal use.

Adults: Apply a thin layer to the affected area as needed. Refer to specific product instructions for optimal use.

Mechanism of action

Dusting powders primarily act by absorbing excess moisture and reducing friction on the skin. This creates a dry environment that inhibits the growth of bacteria and fungi, thereby preventing infections and promoting healing. The physical barrier formed by the powder also protects the skin from irritants.

Pharmacodynamics

The pharmacodynamics of dusting powders involve their ability to absorb moisture and provide a protective barrier on the skin. This action helps to maintain skin integrity, reduces the risk of irritation or maceration, and promotes a conducive environment for healing. The effectiveness can vary based on the specific formulation and active ingredients used.

Pharmacokinetics

Dusting powders are designed for topical application, and they do not generally undergo significant systemic absorption. The pharmacokinetics are largely localized to the site of application. The onset of action is typically immediate upon application, with duration varying based on the formulation and the environment (e.g., moisture, friction).

Pregnancy

Safety during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised as it is not known if dusting agents are excreted in human milk.

Storage

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

Indications

• Dermatophytosis
• Candidiasis
• Tinea corporis
• Tinea pedis
• Tinea cruris
• Seborrheic dermatitis
• Systemic fungal infections

Dosage

Children: Refer to the BNF for Children for dosing information in pediatric patients.

Adults: Refer to specific guidelines or the BNF for detailed dosing information based on the condition being treated.

Mechanism of action

Ketoconazole exerts its antifungal effect by inhibiting the enzyme lanosterol 14-alpha-demethylase, which is crucial in the biosynthesis of ergosterol, a vital component of fungal cell membranes. This disruption leads to increased permeability of the membrane and ultimately results in cell lysis.

Pharmacodynamics

Ketoconazole has a broad spectrum of activity against various fungi, including Candida species, Aspergillus species, and dermatophytes. Its effectiveness is influenced by the pH of the environment, as absorption is enhanced in more acidic conditions. The drug exhibits a time-dependent killing effect, with prolonged exposure contributing to its antifungal efficacy.

Pharmacokinetics

Ketoconazole is well absorbed from the gastrointestinal tract, with a bioavailability that can be affected by food and gastric pH. The peak plasma concentration occurs approximately 1 to 2 hours post-ingestion. It is extensively metabolized in the liver through cytochrome P450 enzymes, particularly CYP3A4, resulting in various metabolites. Ketoconazole has a half-life of about 2 to 3 hours, and its elimination occurs primarily via the bile. The drug can accumulate in certain tissues, including the skin and adipose tissue.

Contra-indications

• Hypersensitivity to ketoconazole or any component of the formulation
• Concurrent use with certain medications that prolong the QT interval
• Adrenal insufficiency
• Liver disease

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Headache
• Dizziness
• Skin rash
• Hepatotoxicity
• QT prolongation

Interactions

• CYP3A4 inhibitors may increase ketoconazole levels
• CYP3A4 inducers may decrease ketoconazole levels
• Concurrent use with anticoagulants may enhance anticoagulant effect
• Anticonvulsants may reduce ketoconazole efficacy

Precautions

• Monitor liver function tests regularly
• Use with caution in patients with a history of liver disease
• Assess for potential drug interactions before initiating therapy
• Monitor for signs of adrenal insufficiency

Pregnancy

Ketoconazole should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is classified as Category C.

Breast-feeding

Ketoconazole is excreted in breast milk; caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Oral tablets
• Topical cream
• Topical shampoo
• Topical foam