Rohynol is usually taken orally but sometimes ground up and snorted. Rohypnol causes the user to feel intoxicated then sleepy. It may last up to eight hours.
Users exhibit slurred speech, impaired judgment and difficulty walking.
It can cause deep sedation, respiratory distress and blackouts. Sometimes the drug causes the opposite effect and the user becomes aggressive. Rohypnol is considered a sexual assault drug because of the potential to cause blackouts and amnesia at high doses. The most common method used to drug someone has been to put it into a drink at a bar, nightclub, or party. The drink would not taste out of the ordinary.