Could make a case cor her being an accomplice to the crime, or mayhaps criminal negligence.
Negligence is the wrong word here. Negligence is defined, if I recall, as disregarding a substantial and unjustifiable risk that a reasonable person would appreciate. I.E. for negligence, you do not need to know the severity the the error you make, it is an ad hoc decision by the state. Oh well.
Recklessness is defined similarly, although it is as "knowing and disregarding a substantial and unjustifiable risk." That one is more applicable here, since she would know about the drugging (assuming she knew, not assuming it happened, we all know it did).
In terms of which is worse, recklessness is worse. And all of this is operating from the model penal code, which may not be adopted in Cosby's state.