Lomustine (or CCNU; marketed under the name CeeNU in U.S.) is an alkylatingnitrosourea compound used in chemotherapy. It is in the same family as streptozotocin. This is a highly lipid soluble drug, and thus crosses the blood-brain barrier. This property makes it ideal for treating brain tumors, and is its primary use. Lomustine has a long time to nadir (the time when white blood cells reach their lowest number).