also rufy, rophy, ruffie, "Rohypnol" by 1989, the name is perhaps a variant on Rohypnol (the erroneous spelling Rophynol is recorded in newspapers and magazines by 1992). The meaning "any drug used to incapacitate someone, especially one secreted into food or drink," is attested by 2002.
Earlier it was also a nickname, typically a variant of Ruth.