Propofol causes pain on injection. True is all except

All phenols irritate skin and mucous membrane. Thus, propofol being an alkylphenol is expected to cause pain in spite of the fact that it is almost isotonic. Pain on propofol injection has also been described as angialgia by some meaning that the pain is due to vascular involvement. Pain on propofol injectionis immediate as well as delayed after 10-20 s. The immediate pain is due to irritation of vein endothelium whereas delayed pain is due to the release of mediators such a kininogen from kinin cascade.