Since ketamine is a potent dissociative anesthetic drug, taking it in large doses and over a long period of time can be very detrimental.
The most serious long-term effect of repeated, high-dose ketamine abuse is a physical tolerance to, and dependence on, the drug. Tolerance means that the person will need to take more of the substance to feel the original effects, and in the case of ketamine, that may lead to very harmful practices to get a more intense high.
People who take ketamine typically ingest the drug orally or nasally; however, it can also be injected, either intravenously or intramuscularly, which increases the risk of damage to veins, muscles, skin, and internal organs. Injectable drugs are more likely to cause skin infections, transmit HIV or hepatitis through needle-sharing, or lead to endocarditis, an infection of the heart valves.
There are also other long-term side effects from abusing ketamine.
Many intoxicating substances lead to cognitive decline, memory difficulty, and mood changes when they are abused for a long time, and ketamine is no exception. People who abuse this anesthetic have trouble with memory, issues with thinking clearly, and mood swings. Impairments in creating new memories, accessing old memories, verbal memory (e.g., forgetting words, names, and conversations), short-term memory, and visual memory continue while the person abuses ketamine. These are likely to improve when a person gets help overcoming ketamine addiction.
Long-term mental side effects specific to ketamine include:
Hallucinogenic drugs are often associated with flashbacks even if they are used once; however, drugs like PCP, DXM, and ketamine can all cause flashbacks too. Also like these other drugs, ketamine can trigger psychosis or schizophrenia in those who are predisposed to these mental health disturbances.
Some people who abuse ketamine for a long time experience changes to vision, including anomalies, which are typically mild. These can make some tasks like driving more difficult.
Ketamine can cause more serious damage to organ systems, especially to the bladder, kidneys, and heart. People who take large doses of ketamine are likely to experience respiratory distress, rapid heart rate, and seizures. Chronic abuse of this drug specifically damages the bladder, leading to inflammation in that organ, incontinence, and permanent harm. Symptoms of ketamine-caused bladder damage include:
Ketamine is highly associated with developing ulcerative cystitis, a form of panful bladder syndrome characterized by damage to the bladder’s tissues leading to chronic, recurring pelvic pain, with ulcers – red, bleeding patches – in the walls of the bladder. According to the Interstitial Cystitis Association, about 5 percent of people with interstitial cystitis, whether it is ulcerative or not, develop end-stage cystitis. This condition is a failure of the bladder, leading to an organ that is hard, extremely painful, and unable to hold urine. About 10 percent of any cystitis case is ulcerative, and abusing ketamine increases the risk of developing this specific type of bladder condition. About 33 percent of people who abuse ketamine, according to one study, developed reduced bladder volume.
Kidney function also declines when ketamine is abused for a long time. Hydronephrosis, or excess fluid in the kidneys caused by a backup of urine, was reported 50 percent of the time in a study. Damage to the bladder may prevent urine from transferring from the kidneys into the bladder, leading to this chronic condition.
This dissociative drug can also cause kidney failure, heart complications, and trouble breathing. While acute effects like heart attack, seizures, stroke, or respiratory failure are more likely to occur during overdose, experiencing an overdose can also lead to damage to internal organs, including the brain.
Although it is not a common date rape drug, ketamine has been used in this scenario. At high doses, ketamine leads to dissociation from reality, inability to feel pain, and impaired vision. A person who experiences date rape is more likely to accidentally consume ketamine; however, recreational consumption of ketamine leaves the individual at risk of becoming a victim of crime, including date rape, theft, or worse. Date rape can lead to contracting a sexually transmitted infection, including herpes or HIV.