ΔE 19.8, loose: different enough that you should pick on purpose. Medium Magenta is a little lighter, much more saturated, cooler than Pink Horror.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Medium Magenta is a little lighter, much more saturated, cooler than Pink Horror.
The same difference applies the other way round: Pink Horror is a little darker, much more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Pink Horror on the colour wheel See Medium Magenta on the colour wheel
All matches: Pink Horror equivalents · Medium Magenta equivalents