Green’s Dictionary of Slang

(Aus.) the strong tranquiliser, Rohypnol.

1996		Google Groups: misc.emerg-services 18 Jan. 🌐 More commonly known on the street in Australia as ‘Rowies’. It is a prescription drug that is readily available on the streets.
2001		A. Campbell Aust. Illicit Drug Guide 367: Rowies: Rohypnol.
2017		T. Spicer Good Girl Stripped Bare 21: He’s on ‘rowies’ — a tranquiliser ten times stronger than Valium.