Topical coal tar overdose may increase the rate of skin irritation and photosensitivity. (s ee section 4.8). Polytar Scalp Shampoo should be used once or twice a week. Wet the hair and massage into the scalp and surrounding skin. Rinse thoroughly and repeat. High dose administration of coal tar to laboratory animals is carcinogenic However, epidemiological evidence that includes prospective and retrospective studies in thousands of patients receiving coal tar therapy followed for more than 40 years do not suggest a potential increased risk of skin or systemic cancer.

Use of this medicine during pregnancy should only be considered if the expected benefit to the mother outweighs the potential risk to the foetus. Polytar scalp shampoo with coal tar is effective in the treatment of psoriasis, eczema, dandruff and other dry skin conditions that may affect the scalp. Coal tar has been shown to be foetotoxic and teratogenic to the offspring of laboratory animals when administered topically, orally or by inhalation at high and maternally toxic doses (see section 5.3). Use of coal tar preparations during lactation should only be considered if the expected benefit to the mother outweighs the potential risk to the infant.

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It is not known whether the topical application of coal tar preparations could result in sufficient systemic absorption to produce detectable amounts in breast milk.

Tar preparations have been used extensively for over 50 years in the management of various skin conditions such as psoriasis, eczema and other dermatoses. The precise mechanism of action is uncertain. Coal tars are known to suppress DNA synthesis in hyperplasic skin, inhibiting mitotic activity and protein synthesis. They decrease epidermal proliferation and dermal infiltration and thus promote a return to normal keratinisation. Coal tar has anti-inflammatory, antibacterial, antipruritic, keratolytic, keratoplastic and vasoconstrictive effects.In a study using a variety of coal tar preparations total urinary poly aromatic hydrocarbons were significantly elevated in patients treated dermally for different forms of dermatoses. The treatment period was for an average of 7 days using 1.5% - 40% coal tar preparations over a body surface area that ranged from 9 to 90%. Therefore some of the hydrocarbons present in coal tar may be absorbed through the skin. The highest levels absorbed depend largely on the body surface area treated and on the duration of exposure. No long term studies have been conducted with the product formulations. Coal tar contains certain chemicals that are mutagenic to microorganisms and mammalian cells in vitro. Topical and oral administration of high doses of coal tar to laboratory animals induces DNA adduct formation. Alopecia, dermatitis, hair colour changes, abnormal hair texture, photosensitivity reaction, skin irritation (including dry skin, erythema, and skin burning sensation). Coal tar preparations have been used, for many years, when recommended by a doctor to treat children however, there is very little documented clinical data in this patient population. The scalp and adjacent areas should be massaged with the fingertips. The hair should then be thoroughly rinsed and the procedure repeated. Taking both of these shampoo applications into consideration, the total leave on time for the shampoo should be 3-5 minutes.