How you use a Syringe in combat?

I have to numb the pain of losing my family and living in this hellish wasteland, so I can slept at night. I am a hardcoe role player.

very poorly, I guess if your really trying to go for a pacifist character and trying not to kill anyone, I tend to hate effects that are inconsistent and based on "chance" that said the one that makes them loose track of you seems to be 100%, so like I said pacifist :/

Load it into the syringer as ammunition

Yep- hit the button you would use to reload a normal weapon and it will bring up a menu to select the Syringer ammo you have crafted and have available in your inventory.

I need a weapon called syringer to use it...ok i thought maybe you threw it like a grenade.