When severe, the muscle contractions can result in bone fracture or in kidney damage or failure as a consequence of muscle cells breaking down. Very high doses of PCP can cause convulsions, coma, hyperthermia, and death. PCP's effects are unpredictable. Typically, they are felt within minutes of ingestion and last for several hours. Some users report feeling the drug's effects for days.
Some users report feelings of invulnerability and exaggerated strength.
PCP users may become severely disoriented, violent, or suicidal. Repeated use of PCP can result in addiction, and recent research suggests that repeated or prolonged use of PCP can cause withdrawal syndrome when drug use is stopped. Much of the ketamine sold on the street has been diverted from veterinarians' offices. Although it is manufactured as an injectable liquid, in illicit use ketamine is generally evaporated to form a powder that is snorted or compressed into pills. Ketamine's chemical structure and mechanism of action are similar to those of PCP, and its effects are similar, but ketamine is much less potent than PCP with effects of much shorter duration.