The effects of ketamine vary, depending on the size and regularity of the dose, as well as the user's tolerance for the drug. In general, ketamine is a powerful painkiller, often used in controlled doses as an anesthetic and as a sedative. Some experts prefer the drug over other anesthetics, as it tends to stimulate the circulatory system, rather than suppress it like the others do. A slight feeling of euphoria might set in with initial doses of ketamine, with larger doses eventually leading to hallucinations. Abuse of the drug can cause serious health problems, chief among which is brain damage.
The drug is classified as an N-Methyl-D-aspartic acid (NDMA) receptor antagonist, impairing the receptors' function and blocking off effects from glutamate, an excitatory neurotransmitter. This action significantly reduces the sensation of pain and calms the patient's mood. Stronger doses bind to opioid receptors in the brain, which enhance the analgesic effects while introducing sensations of euphoria. Patients under the effects of ketamine might eventually enter a dreamlike state in which their bodies feel like they're floating; hallucinations accompany the sensation in a number of cases. Reports of the experience have led many individuals to use ketamine as a recreational drug.
Substance abuse, however, can lead to many negative effects of ketamine. The euphoric, floating sensations and hallucinations induced by high doses of the drug can displace the user's perception from reality, resulting in anxiety and paranoia. Some users state that the sensation is similar to falling down a bottomless hole, and it can be paralyzing. It is not uncommon for individuals to feel nauseated while under the effects of ketamine. Frequent use can also lead to a dissociation with reality, resulting in a slew of possible psychological disorders.
Medical effects of ketamine, on the other hand, can prove to be fatal. Although small doses of the drug can be beneficial in boosting the circulatory system, larger doses can suppress breathing. Tampering with the brain's normal functioning through frequent use of ketamine can also lead to a dependence on the drug; users often suffer withdrawal symptoms such as tremors when taken off the drug. Heavy or regular ketamine use can cause the development of irreparable lesions in the brain, resulting in issues involving poorer cognitive abilities and impaired neurological function. Studies have shown that long-time ketamine users also have a higher incidence of kidney problems, although this can be accounted for by the fact that the lifestyle associated with drug abuse often includes other damaging factors like alcohol abuse.