Dammitall (said like 'Damn it all'): a made up drug name. Much like the phrase 'take a chill pill',it refers to someone saying 'Damn it' repeatedly while incredibly angry or in a fit of rage and someone tells them that they 'took some Dammitall'
Dean: Damn it! I broke my iPod, Damn it!
Jesse: Holy Shit Dean, looks like you took some Dammitall