What is Ketamine?
Ketamine is a medication whose effects are dependent on its serum concentration. At higher doses/concentrations, it acts as a general anesthetic. It safely creates an unconscious state and allows medical procedures to be performed without pain or other discomfort. At lower doses, it relieves chronic pain without requiring a loss of consciousness. At even lower doses, it effectively treats acute and chronic psychiatric conditions, including unremitting depression and suicidal thoughts. It is unique in that its positive effects can last well after a treatment session, even though the body has already completely metabolized it. This distinguishes it from many medicines we use in psychiatry because it does not need to be taken daily. Furthermore, these long-lasting effects can sometimes reduce or replace other psychiatric or pain medicines.
How Does it Work?
It Affects Neuroreceptors
Ketamine first works by interacting with the neuroreceptors in our brains. Neuroreceptors are protein structures located on the membranes of our nerves or other specialized cells. When certain molecules plug into (bind) neuroreceptors, they trigger unique responses. Ketamine is one of these binding molecules, as are serotonin, dopamine, norepinephrine, and other molecules.
Ketamine Reacts With Specific Neuroreceptors
Ketamine interacts with several neuroreceptors, but most significantly with one called the "NMDA" receptor. This receptor helps regulate the release of the molecule glutamate in the body. Ketamine triggers the release of extra glutamate and raises its level. To a lesser extent it interacts with opioid receptors (pain reduction), GABA receptors (relaxation), and other neuroreceptors.
What Does That Do?
This increase in glutamate stimulates a number of subsequent reactions within and around the neurons. We still do not know which reactions are most important to ketamine's beneficial effects. We do know glutamate stimulates changes in the connections between neurons, and these changes last well beyond the time ketamine has left your system.
How Does That Help Me Feel
Better?
We believe that some of ketamine's helpful effects are created when it causes changes in neuron connections. The changes may include altering the pathway your sensory inputs (things you touch, see, smell, etc.) take to reach your brain. When the signals are re-routed to more appropriate places, there seems to be an improvement in psychiatric and pain symptoms.