Green’s Dictionary of Slang

suffering from venereal disease.

1936		K. Mackenzie Living Rough 128: They say he got dosed up, too.
1954		(con. 1940s) T.A.G. Hungerford Sowers of the Wind 170: Then some M.O. [...] tells us that the girls are all dosed up, and not to go playing around.
1966		(con. 1958) R. Farina Been Down So Long (1972) 197: I’m dosed, baby. Clap.
1969		‘Groupie Gloss.’ on A. Lorber Groupies [album] Dosed-up: having contracted a venereal disease.