polidocanol

Polidocanol is a local anaesthetic and antipruritic component of ointments and bath additives. It relieves itching caused by eczema and dry skin. It is formed by the ethoxylation of dodecanol.
The substance is also used as a sclerosant, an irritant injected to treat varicose veins, under the trade names Asclera, Aethoxysklerol and Varithena. Polidocanol causes fibrosis inside varicose veins, occluding the lumen of the vessel, and reducing the appearance of the varicosity.
The FDA has approved polidocanol injections for the treatment of small varicose (less than 1mm in diameter) and reticular veins (1 to 3mm in diameter). Polidocanol works by damaging the cell lining of blood vessels, causing them to close and eventually be replaced by other types of tissue.
Pure polidocanol for pharmaceutical use