Potentially, 10 more people with bipolar depression per 1000 may experience brief improvement, but not cessation of symptoms, one day following treatment. These estimates are based on limited available research.In February 2022, the US Food and Drug Administration issued an alert to health care professionals concerning compounded nasal spray products containing ketamine intended to treat depression: "There is no FDA-approved ketamine nasal spray product. Compounded drugs are not FDA-approved, which means FDA has not evaluated their safety, effectiveness, or quality prior to marketing." Near-death experience
Most people who were able to remember their dreams during ketamine anesthesia report near-death experiences (NDE) when the widest possible definition of an NDE is used. Ketamine can reproduce features that commonly have been associated with NDEs. A 2019 large-scale study found that written reports of ketamine experiences had a high degree of similarity to written reports of NDE in comparison to other written reports of drug experiences. Seizures
Ketamine is sometimes used in the treatment of status epilepticus that has failed to adequately respond to standard treatments, although only limited evidence (case studies and no randomized controlled trials) exists in its favor. Contraindications
Main contraindications for ketamine:
Severe cardiovascular disease such as unstable angina or poorly controlled hypertension
Increased intracranial or intraocular pressure.
Moreover, animal studies and at least three human case reports have found no interaction between ketamine and the monoamine oxidase inhibitor (MAOI) tranylcypromine, which is of importance as the combination of a monoamine reuptake inhibitor with an MAOI can produce severe toxicity such as serotonin syndrome or hypertensive crisis. Collectively, these findings shed doubt on the involvement of monoamine reuptake inhibition in the effects of ketamine in humans. Ketamine has been found to increase dopaminergic neurotransmission in the brain, but instead of being due to dopamine reuptake inhibition, this may be via indirect/downstream mechanisms, namely through antagonism of the NMDA receptor.Whether ketamine is an agonist of D2 receptors is controversial. Early research by the Philip Seeman group found ketamine to be a D2 partial agonist with the potency similar to that of its NMDA receptor antagonism. However, later studies by different researchers found the affinity of ketamine of >10 μM for the regular human and rat D2 receptors, Moreover, whereas D2 receptor agonists such as bromocriptine are able to rapidly and powerfully suppress prolactin secretion, subanesthetic doses of ketamine have not been found to do this in humans and in fact, have been found to dose-dependently increase prolactin levels. Imaging studies have shown mixed results on inhibition of striatal [11C] raclopride binding by ketamine in humans, with some studies finding a significant decrease and others finding no such effect. However, changes in [11C] raclopride binding may be due to changes in dopamine concentrations induced by ketamine rather than binding of ketamine to the D2 receptor.