An hour before we spoke, Darragh O’Carroll, an emergency room physician from Hawaii, had just given an elderly patient a sedating shot of ketamine. The man had pneumonia and was acting confused and fidgety, making him hard to treat.

“Not only it was a pain control for him when I was putting needles into his neck, but it also kept him still,” O’Carroll says. “And with very minimal risk of lowering his blood pressure.”

Ketamine’s use as an anesthetic — and not as a party drug — is wides