A drug used alone or with dabrafinib to treat melanoma that cannot be removed by surgery or has spread to other parts of the body. It is used with dabrafinib to treat non-small cell lung cancer that has spread to other parts of the body. 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 MEK 1 and MEK 2. 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.