About

Providing straightforward information pertaining to drugs, drug use & drug policy. The Grey Pages promotes drug-related literacy and advocates a system of viable and tolerant drug policies. This is my personal collection of commentaries, essays, tid-bits, and other such writings on everything ranging from drug use, drug policy and drug-myths, to drug-science, addiction, human behavior, and the workings of the human brain. I started this blog with a particular focus on opioids, and over the past year have found my interest gravitate toward the intriguing, ever-changing world of designer intoxicants (i.e. "research chemicals" or "designer drugs").

Wednesday, November 9, 2011

Ketamine: Drug Information Page

Ketamine is an anaesthetic drug of the dissociative type. Produces effects similar to PCP, dextromethorphan, tiletamine and nitrous oxide. Popular for recreational & medical use.

Discovered by Parke Davis Co in the early 1960's as an alternative to their other anaesthetic PCP, which had been associated with neurotoxicity and psychotomimetic side effects - These "bizzarre" side effects may be desireable for recreational drug users, but have been described as terrifying for medical patients, many of whom have complained about these effects once awakened from surgery. Ketamine produces similar effects to PCP at a dose ratio of 4/1 (ketamine/pcp). PCP has been removed from the market (for human use) and replaced with ketamine, which is used in both humans and animals.

Use:

Most commonly given in the hospital setting. Low doses produce analgesia while higher doses produce anaesthesia. Ketamine is unique in that with anaesthetic doses it produces stimulation of vital functions rather than depression.

Used as a general anaesthetic/analgesic during surgery, along with other basic components of anaesthesia such as opioid analgesics, sedatives and neuromuscular blocking agents.

Widely used in veterinary medicine as an anaesthetic & analgesic.

Used as a supplement to epidural anaesthesia/analgesia typically by the IV route.

Also given alone or with additional drugs for procedural sedation and emergency analgesia in a field setting (i.e. auto-accidents with trapped subjects & in military combat zones). Its use in trauma is because of its ability to increase or maintain cardiac output, which is especially desireable in cases of blood loss where a subject's blood volume is unknown. It is often preferred in the absence of ventilation equipment due to its lack of respiratory depressant effect.

Ketamine is widely used as a veterinary anaesthetic.

Low doses are useful in relieving neuropathic pain. Low doses may be given as a supplement to narcotics in cases of neuropathic, cancer related, or other forms of severe pain.

Off label or investigational uses include Complex Regional Pain Syndrome and alcohol & opioid addiction.

Observed to be particularly effective in relieving symptoms of refractory major depression. Single parenteral doses of ketamine have been shown to produce significant relief of symptoms within hours of injection, lasting up to a week after injection - This was observed in multiple subjects with major depressive disorder which had consistently failed to respond to other treatments.

Pharmacology & Chemistry

NMDA receptor antagonist, sigma receptor agonist and dopamine reuptake inhibitor. Shows a weak affinity for the mu receptor in high doses. Its binding at the NMDA receptor prevents the binding of the excitatory neurotransmitter glutamate (a positive modulator of ion channel activity), the result being an inhibition of signal transduction in certain areas.

Molecular analogue of PCP. Chemically it is a bicyclic ketone compound with an arylcyclohexylamine core. It is chemically designated ((RS)-2-(2-Chlorophenyl)-2-(methylamino)cyclohexanone).

Racemic compound composed of an (R) enantiomer and an (S) enantiomer. (S)-ketamine has stronger sedative & analgesic properties with 4x greater affinity for the NMDA (PCP-subtype) receptor - (S) is sometimes used as a single isomer product. (R)-ketamine is a stronger sigma agonist than the (S) enantiomer. Actions at the sigma receptor are believed to lower the seizure threshold.

Effects

Ketamine is very short acting. Effects generally last 30 to 60 minutes by any route.

Produces dissociative anaesthesia. As such, its effects differ in nature from drugs of the tryptamine or phenethylamine classes, (which could more likely be considered "hallucinogens" in the proper sense). Instead, dissociatives such as ketamine produce a dose dependent separation of the conscious mind from sensory perception of one's body & surroundings, in some cases allowing a user to experience complete depersonalization - characterized by the complete loss of one's sense of identity, unawareness or oblivion to the outer world, and a shockingly realistic experience of alternate realities or dimensions which exist only inside one's brain chemistry - or as some have theorized, a reality which exists outside of space & time or inside one's soul. Some may speculate that such an experience serves as a glimpse of one's reality before existence & birth, or what one might experience after death.

Effects in low to moderate doses include analgesia, excitement, euphoria and altered senory perception. Effects in high doses include sedation, ataxia (trouble walking characterized by robotic leg movements - i.e. the robo-walk), slurred speech, strange utterances or random words, incoherent sentence structure, meaningless gibberish, aphasia (inability to speak), numbness, double vision, profoundly altered state of reality, loss of sensory perception (i.e. mind/body dissociation), complete loss of motor-ability (essentially equivalent to paralysis), out of body experiences, and time dilation. The author can attest to every one of these occurences (but rather with DXM) with the exception of out of body experience. Side effects of ketamine are similar to those of DXM and include hypertension, nausea & vomiting, hypersalivation, and respiratory depression/stimulation.


Effect Summary


The effects of this drug are relatively short lasting. The drug takes effect after anywhere from 1 minute to 10 minutes, depending on the route of administration. Peak effects are experienced at about 20-40 minutes and rarely exceed an hour in duration. This applies to both intranasal and intramuscular use.

Euphoria

Body buzz

Increased energy

Megalomania & changes in ego

Sense of invincibility

Increased self confidence

Dose dependent sedation or stimulation

Analgesia

Dose dependent anaesthesia

Empathy toward others & increased sociability

Distortion and loss of sensory perceptions (dose dependent)

Closed eye or open eye visuals

Intense body buzz

Complete mind/body dissociation in high doses (very bizarre)

Distorted perceptions of reality or loss of self awareness

Amnesia

Slurred speech

Out of body experience

Distorted time perception

Ataxia and impaired motor coordination

Increased heart rate or depression of heart rate, respiratory depression, nausea & vomiting

1 comment:

  1. I have a topical cream compounded for me with Ketamine as the active ingredient. It is effective on neurological pain for a couple of hours and I experience none of the "side effects".

    ReplyDelete