Is there a macro that can do this?

[Elvenbane-kazzak]

Add [harm] to the start of the options:

#showtooltip
/cast [harm] [@targettarget,harm,nodead] [] Shadow Word: Death

More advanced version:

@Elvenbane-kazzak

Offensive Macro for Healers

This macro is for healers who want to dps without switching to enemy targets. Basically allows you to dps while having fiendly players targeted or moused over.

Mouseover Enemy: Cast on Mouseover
Target Enemy: Cast on Target
Mouseover Friend Targeting Enemy: Cast on Friend’s Target
Target Friend Targeting Enemy: Cast on Friend’s Target
Default casting behavior. This condition also serves to generate the correct tooltip.

#showtooltip
/cast [@mouseover,harm,nodead] [harm] [@mouseovertarget,harm,nodead] [@targettarget,harm,nodead] [] SPELL