Scopolamine

Scopolamine (also referred to as hyoscine hydrobromide or scopolamine hydrobromide) is a drug used for motion sickness.

Usage
Scopolamine is used to treat motion sickness, sea sickness (leading to its popularity with scuba divers), gastrointestinal spasms, renal or biliary spasms, irritable bowel syndrome, clozapine-induced drooling, bowel colic, and eye inflammation. It is also used, in some cases, as a pre-medication to surgeries, usually those meant to reduce respiratory tract secretions.

Uncommonly, there are side-effects to using the drug. They usually range from a dry mouth to itching. Rarer side-effects include agitation, confusion, restlessness, and even hallucinations, though these have a probability of less than 0.1% in occurrence.

Criminal Minds
In Mr. Scratch, serial killer by proxy Peter Lewis used scopolamine as an ingredient for an extremely powerful dissociative agent, which would induce psychotic breaks in potential victims. Reid states that the drug makes people highly suggestible. However, the episode depicts the administration of scopolamine (via air vents) inaccurately, as the drug only exists in a liquid or powder form, making said administration implausible. The drug also takes at least ten minutes to start taking effect when it is injected directly, or up to four hours if absorbed through the skin; in the episode, the drug's effects seem to be near-instantaneous.