What is Polidocanol? Is it better than sclerotherapy for spider veins? Does it cause "shadowing"? Is it available in the US?

Polidocanol(trade name Asclera) is FDA approved and available in the US for the treatment of spider veins.  Polidocanol is classified as a detergent meaning that it can be converted into a foam solution for sclerotherapy.  It can be used in several different concentrations and is about 1/2 as strong as tetradecyl which is another detergent sclerotherapy solution which has been used for years.  In addition to this, polidocanol has minimum side effects and no discomfort on injecting.

Polidocanol is a sclerosing agent, meaning it is used as an injection,either as a liquid or as a foam, to treat a variety of vein conditions, including telangiectasias, spider veins, reticular veins, and varicose veins.  It offers the potential advantage of being more comfortable during injection that other agents (e.g. sodium tetradecyl sulfate, hypertonic saline) as its molecular structure works as an anesthetic (numbing agent) in the area of injection.  According to published clinical studies, polidocanol offers a decreased side effect profile compared to other agents used in sclerotherapy, including a decreased chance of pigmentation and ulceration.