The phrase "drug up" is primarily used in informal language and slang to refer to someone who is under the influence of drugs, or to describe the process of taking drugs. However, there are many other ways to express similar ideas without resorting to this particular phrase. Some synonyms for "drug up" might include "intoxicated," "high," "stoned," or "drunk." Other options might include "under the influence," "using drugs," or "abusing substances." Each of these alternatives offers a different emphasis or shade of meaning, and can help writers and speakers to express their ideas more clearly and effectively.