GILL ANTI-DANDRUFF SHAMPOO

Indications

• Dandruff
• Seborrheic dermatitis

Dosage

Children: Refer to BNF for Children for appropriate dosing information in paediatric patients.

Adults: Refer to BNF for specific dosing guidelines based on formulation and condition being treated.

Mechanism of action

Pyrithione exerts its antifungal effects by increasing copper uptake in target organisms, forming a CuPT complex that facilitates copper transport across membranes. This leads to inactivation of iron-sulfur (Fe-S) cluster-containing proteins, impairing fungal metabolism and growth. Additionally, pyrithione acts as an ionophore, enhancing copper transport and slightly increasing zinc levels in affected microorganisms.

Pharmacodynamics

Pyrithione zinc demonstrates a broad antimicrobial spectrum, effectively targeting fungi, including Malassezia species, as well as gram-positive and gram-negative bacteria. Its antifungal activity helps reduce the fungal load on the scalp, leading to decreased production of free fatty acids, thus alleviating symptoms associated with dandruff.

Pharmacokinetics

Pyrithione is primarily used topically, resulting in localized effects with minimal systemic absorption. The pharmacokinetic profile in humans is not extensively detailed, but its action is concentrated at the site of application, particularly on the scalp and skin.

Adverse effects

• Skin irritation
• Allergic reactions
• Burning sensation
• Itching

Precautions

• Avoid contact with eyes
• Discontinue use if irritation occurs
• Use with caution in patients with a history of hypersensitivity to pyrithione or its components

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed and the benefits justify the potential risks.

Breast-feeding

Limited data available. Caution is advised as it is not known if pyrithione is excreted in human milk.

Storage

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

Formulations

• Topical shampoo
• Topical cream
• Topical lotion

Mechanism of action

Inhibition of fungal growth by pyrithione zinc is linked to increased copper uptake and cellular levels of copper, which is demonstrated by decreased CTR1-lacZ expression and slightly increased CUP1-lacZ expression in affected microorganisms. The coordination complex of pyrithione zinc dissociates, and pyrithione ligand forms a CuPT complex from available extracellular copper in the target organism. Pyrithione acts as an ionophore, interacting nonspecifically with the plasma membrane to shuttle copper into the cell, and facilitates copper transport across intracellular membranes. Copper may be shuttled into the mitochondria. Copper inactivates iron-sulfur (Fe-S) cluster-containing proteins via a mechanism similar to that described for copper-induced growth inhibition in bacteria. Decreased activity of Fe-S proteins leads to inhibition of fungal metabolism and fungal growth. Pyrithione zinc has been shown to slightly increase the levels of zinc.

Pharmacodynamics

Pyrithione zinc has a broad antimicrobial spectrum of activity, including fungi, gram-positive and gram-negative bacteria. Pyrithione zinc is effective against Malassezia and all other fungi, especially the Malassezia species found on scalp. In patients with dandruff, treatment with pyrithione zinc reduced the amount of fungus on the scalp, which reduces the amount of free fatty acids, thereby reducing scalp flaking and itch.