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

Polidocanol is a sclerosant solution classified as a chemical detergent.  It can be used in foam solution sclerotherapy but is not FDA approved in the United States at this time.  There are alternative solutions in the United States and these can be administered by a board certified vein specialist.

There are several ways to treat spider veins in the legs.
The most common, and still considered the 'gold standard', is with sclerotherapy.
Laser can also be a good option if the vessels are so tiny that it is nearly impossible to cannulate them with a needle and sometimes as an option when treating large, bulging vessels by entering inside of the vessel and sealing them from within.
There are several sclerosants available and all will adequately do the job. Sometimes it is just personal preference from the clinician.
Polydoconol can be obtained and used in the U.S. This is actually the choice method in our office. The average normal concentrations can be 0.25% to a 1.0% solution, depending on vessel size being treated. The shadowing that you are referring to is actually an increase in the pigment of the skin that can occur after the procedure. One significant way to minimize this is to be as sun-free as possible prior to the treatment. Bleaching creams can also help to reduce this effect. By applying the cream prior to the procedure and afterwards can help reduce the chance that the pigment cells will be activated as strongly, and thereby reduces the 'shadowing effect'.

Polidocanol is a solution used for the vein injections called sclerotherapy. It is not FDA approved, but so far it is one of the best agents to treat spider veins or telangectasias. During the procedure a solution which is irritating to the vein is injected into the vessel with a very fine needle causing irritation and inflammation in the wall of the vein resulting in scarring of the vessel. The results of the sclerotherapy depend also on how well patient is wearing the compression stockings, which are prescribed by the physician.

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.

Polidocanol and Sotradecol are both considered detergents. They are both FDA approved.  The Shadows you mentioned may be either Post Injection Hyperpigmentation which is inflammatory in nature and may take a few months to resolve.  It may also be matting.  Post injection hyperpigmentation  does occur in both but according to most literature to a less degree in asclera.The risk of matting  telangiectasias can  be minimized by making sure not to rupture the vessel by injecting with too much pressure.

and the brand name is Asclera.  Polidocanol along with STS are in the "detergent" class of sclerosing agents and considered the safest.  The "shadowing" you mention may be post-inflammatory hyperpigmentation (PIH) which sometimes may take up to 1-2 months to resolve.  It is also possible that the shadowing is from formation of grouped or matted telangiectasia near the treated vessel.  Asclera can cause PIH but less commonly than STS.  The rish of this temporary pigmentation can be further minimized by matching the vessel size with the right concentration.  Asclera comes in two concentrations: 0.5% and 1.0%  The risk of matted telangiectasia can also be minimized by rate of injection and volume of solution used. 

Polidocanol (Aethoxysclerol) is not a new sclerosant for varicose veins, it has been used for decades in europe.  It is finally available in the USA but not Canada as of yet officially.  It may produce less "shadowing" on the skin after treatment but this is usually a result of the hemosiderin from the blood that leaks out of the vessel when it is treated.  Polidocanol is a bit of an anaesthetic as well so for injection purposes, it is less painful and there are supposedly less side effects as well. 

It is a very good sclerosant, you can try it or STS, both of them work quite nicely to sclerose veins.

Cheers

Polidocanol (Asclera) got U.S. FDA approval March 2010.  The "shadowing"  you refer to could be temporary discoloration which is still a potential side effect with Asclera.  The "shadowing" you refer to may also be matting of veins which is the occurrence of multiple tiny little vessels that show up after having sclerotherapy.  That can be treated with Vbeam laser.  Asclera still has potential side effects which can be minimized by seeing a skilled provider. 

Polidocanol is a sclerosant used for the treatment of leg veins. While available and popular in Europe, Polidocanol is still not FDA-approved in the United States. It is expected to be approved in the U.S. sometime in 2010. In general, a sclerosing solution (sclerosant) works by causing irritation and inflammation in the wall of the vein into which it is injected. This results in fibrosis of the vessel, followed by occlusion of the lumen, thereby reducing the appearance of the vein (varicosity). It is important for patients to also wear compression garments (prescribed by the physician) following their sclerotherapy treatments. For patients to get excellent results, typically several treatments are required and should be spaced about 4-6 weeks apart.