The possible side effects of ketamine administered as an infusion include the following: Nausea and vomiting Swollen eyelids, face, lips, or tongue Hives and rashes that itch intensely Irregular heartbeat, either too fast or too slow High blood pressure, chest pain, and shortness of breath Disturbances of perception, like blurred vision and intense colors Dissociation or out-of-body experiences Confusion and paranoia.