Ketaminhydrochlorid Chemische Eigenschaften,Einsatz,Produktion Methoden
R-S?tze Betriebsanweisung:
R22:Gesundheitssch?dlich beim Verschlucken.
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
S-S?tze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
Chemische Eigenschaften
Ketamine hydrochloride is Off-White Solid
Verwenden
Anesthetic (intravenous).
Controlled substance (depressant).
Definition
ChEBI: The hydrochloride salt of ketamine.
Biologische Funktion
Ketamine is a cyclohexanone derivative whose pharmacological
actions are quite different from those of the
other IV anesthetics. The state of unconsciousness it
produces is trancelike (i.e., eyes may remain open until
deep anesthesia is obtained) and cataleptic; it has frequently
been characterized as dissociative (i.e., the patient
may appear awake and reactive but does not respond
to sensory stimuli). The term dissociative
anesthesia is used to describe these qualities of profound
analgesia, amnesia, and superficial level of sleep.
Allgemeine Beschreibung
Ketamine is formulated as an acidic solution, pH 3.5 to 5.5,available with or without 0.1 mg/mL benzethonium chloridepreservative. Ketamine is marketed as the racemic mixtureand some properties of the individual isomers have beenelucidated. Ketamine is a rapid-acting agent that can beused for induction, used as the sole agent for general anesthesiaor combined with other agents. Unlike the proposedmechanism of action for most anesthetics, ketamine doesnot act at the GABAA receptor. Ketamine acts as a noncompetitiveantagonist at the glutamate, NMDA receptor, anonspecific ion channel receptor. The NMDA receptor is locatedthroughout the brain and contains four well-studiedbinding sites. The primary binding site binds L-glutamate,NMDA, and aspartate. The allosteric site binds glycine,which facilitates primary ligand binding. There is also amagnesium binding site that blocks ion flow through thechannel and a phencyclidine (PCP) binding site that blocksthe ion channel when occupied. Ketamine is believed tobind to the PCP site in a stereoselective manner and blockthe ion flow in the channel. By blocking the flow ofcalcium ions into the cell, ketamine prevents the calcium concentration from building and triggering excitatorysynaptic transmissions in the brain and spinal cord.
Biologische Aktivit?t
Non-competitive NMDA receptor antagonist (EC 50 values are 13.6 and 17.6 μ M for NR1/NR2A and NR1/NR2B subunit combinations respectively). Dissociative anesthetic.
Clinical Use
Like other dissociative anesthetics, ketamine isabused for its hallucinatory effects. Most of the illegallyused ketamine comes from stolen legitimate sources, particularlyfrom veterinary clinics or smuggled in fromMexico.
Ketamine is metabolized via N-demethylation to formthe main metabolite norketamine. Norketamine has aboutone third the potency of the parent compound. Minor metabolicpathways include hydroxylation of the cyclohexanonering; hydroxylation followed by glucuronide conjugation,and hydroxylation followed by dehydration to the cyclohexenonederivative.
Nebenwirkungen
The most serious disadvantage to the use of ketamine is
its propensity to evoke excitatory and hallucinatory
phenomena as the patient emerges from anesthesia.
Patients in the recovery period may be agitated, scream
and cry, hallucinate, or experience vivid dreams. These
episodes may be controlled to some extent by maintaining
a quiet reassuring atmosphere in which the patient
can awaken or if necessary by administering tranquilizing
doses of diazepam.
Other reported side effects include vomiting, salivation,
lacrimation, shivering, skin rash, and an interaction
with thyroid preparations that may lead to hypertension
and tachycardia. Ketamine also may raise intracranial
pressure and elevate pulmonary vascular resistance, especially
in children with trauma or congenital heart disease.
Increases in intraocular pressure also may occur,
and vigilance is required if ketamine is used in ocular
surgery.
Sicherheitsprofil
Poison by
intramuscular, intraperitoneal, and
intravenous routes. Moderately toxic by
ingestion. Human systemic effects by
intravenous and possibly other routes:
analgesia, coma, hallucinations and distorted
perceptions, dyspnea. An experimental
teratogen. An anesthetic. When heated to
decomposition it emits very toxic fumes of
Cland NOx.
Ketaminhydrochlorid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
