Dr. Karsten Bartels, an associate professor specializing in anesthesiology at the University of Colorado Anschutz Medical Campus, said ketamine's use in hospitals is well-established. It must be administered with caution, Bartels added, and an understanding of the patient. "One has to take into account, for example, what the patient's baseline status is," Bartels said. "If you have a patient who maybe takes a stimulant as a prescription medication or if somebody has taken illicit stimulants, such as cocaine or amphetamines or something like that, then the side-effect profile of ketamine would be very undesirable."