A drug used with dabrafenib to treat anaplastic thyroid cancer and non-small cell lung cancer that are advanced or have spread to other parts of the body. It is also used alone or with dabrafenib to treat certain types of melanoma. Trametinib dimethyl sulfoxide is used in patients whose cancer has a mutated (changed) form of a gene called BRAF. It is also being studied in the treatment of other types of cancer. Trametinib dimethyl sulfoxide blocks proteins called MEK1 and MEK2. This may help keep cancer cells from growing and may kill them. Trametinib dimethyl sulfoxide is a type of kinase inhibitor and a type of targeted therapy. Also called Mekinist.