coal tar extract: clinical use

Prescribing considerations

• Confirm the diagnosis and assess severity; coal tar shampoo may form part of treatment for scalp psoriasis, while more severe disease may require additional treatment or specialist review.
• The selected product is not recommended below 12 years because safety and efficacy data are insufficient.
• Counsel about local irritation, possible photosensitivity and temporary discolouration of grey, blonde, bleached or tinted hair.
• Consider fragrance, parahydroxybenzoate and other excipient allergies.

Contraindications and cautions

• Hypersensitivity to coal tar or any excipient
• Acutely inflamed or broken skin
• Erythrodermic psoriasis
• Generalised pustular psoriasis

Monitoring

• Assess clinical response and local tolerability.
• Stop treatment if significant irritation or hypersensitivity develops.
• No routine laboratory monitoring is specified for this wash-off shampoo.

Clinical pharmacology

Coal tar inhibits mitotic activity, DNA synthesis and protein synthesis in hyperplastic skin, reducing epidermal proliferation and dermal infiltration. Systemic absorption from a shampoo is expected to be extremely low because it is rinsed off.

Formulation and product differences

• The selected formulation is a translucent amber, fragranced, wash-off shampoo.
• It contains methyl and propyl parahydroxybenzoates and multiple fragrance allergens that may cause local or delayed allergic reactions.
• The selected Neutrogena T/Gel Therapeutic Shampoo is marked as discontinued on eMC.