A character who has taken drugs, willingly or not, must fight off the effects of the drug.
Resisting the effects requires a reflexive Stamina + Resolve roll. This roll is not contested but it is modified by the potency of the drug ingested.
Only one success is necessary for a character to regain her senses.
In the case of some drugs, this roll must be made once per hour, once per scene — or even once per turn, in the case of strong hallucinogens or narcotics.