Polidocanol is a local anaesthetic and antipruritic

Antipruritic

Antipruritics, also known as anti-itch drugs, are medications that inhibit the itching that is often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those from mosquitoes, fleas, and mites, and contact dermatitis and...

 component of ointments and bath additives. It relieves itching caused for example by dry skin conditions such as eczema

Eczema

Eczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...

.

The substance is also used as a sclerosant

Sclerotherapy

Sclerotherapy is a procedure used to treat blood vessels or blood vessel malformations and also those of the lymphatic system. A medicine is injected into the vessels, which makes them shrink. It is used for children and young adults with vascular or lymphatic malformations...

, an irritant

Irritation

Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...

 injected to treat varicose veins

Varicose veins

Varicose veins are veins that have become enlarged and tortuous. The term commonly refers to the veins on the leg, although varicose veins can occur elsewhere. Veins have leaflet valves to prevent blood from flowing backwards . Leg muscles pump the veins to return blood to the heart, against the...

, under the trade names Asclera and Aethoxysklerol. Polidocanol causes fibrosis

Fibrosis

Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This is as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue...

 inside varicose veins, occluding the lumen

Lumen (anatomy)

A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...

of the vessel, and reducing the appearance of the varicosity.

The FDA has approved polidocanol injections for the treatment of small varicose (less than 1 mm in diameter) and reticular veins (1 to 3 mm 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.