Prescription drug «Ketamine» is a group of drugs used for anesthesia and analgesia. In the past this medicine was widely used in veterinary medicine.
The history of creation
The substance, called «Ketamine», was first synthesized in 1962 by American researcher Calvin Stevens. The scientist worked at Parke-Davis, trying to find a formula safe anesthetic that could be an alternative phencyclidine possessing a number of dangerous side effects (the drug was causing the hallucinations, could provoke an epileptic seizure, and was also neurotoxic).
Three years later, «Ketamine», then known under the working title «CI-581» (clinical investigation 581), for the first time tested in practice. After the first application in the clinic, the drug was used by American soldiers, who in the late 1960-ies served in Vietnam. In 1970, when «Ketamine» in the US has allowed for widespread use, the drug became the first non-inhalation anesthetic, the introduction of which was observed a minimal effect on the circulation and respiration. Subsequently, the drug has been actively used in psychiatry.
The use of «Ketamine» was significantly reduced because of deaths, which in the period of 1987-2000 years were identified in the United States and Europe. The dead used the remedy in a dosage that was much higher than recommended, due to some side effects of the drug. The fact that «Ketamine» by that time, gained dubious popularity as a drug after the book «Journey Into the Bright World» Marcia Moore and Howard Alltounian, and «the Scientist» by John Lilly. In our days the drug is used primarily in veterinary medicine and as an anesthetic in military medicine (in developing countries).
Use in the Soviet Union and Russia
In the USSR, the first research related to the use of «Ketamine» in the treatment of alcoholism and drug addiction in the mid 1980-ies began to conduct Eugene Krupitsky. Work, which lasted about two decades, was discontinued due to the tightening of Russian legislation. Since the early 1990-ies, against the background of the emergence in our country of so-called psychedelic literature, «Ketamine» has been increasingly used as drugs.
According to the Federal law from 08.01.1998 n 3-FZ «On narcotic drugs and psychotropic substances», the drug was included in the list of psychotropic drugs. Five years later, when it created the Federal drug control service, and the law made a number of amendments in Russia has dramatically decreased the use of «Ketamine» in veterinary medicine.
Now the use of this drug for medical purposes is strictly regulated, for violation of the rules imposed fines. «Ketamine» can apply only to licensed institutions, including veterinary. The drug they must keep in the safe, equipped with dual alarm.
In the past the domestic veterinarians widely used «Ketamine» as an anaesthetic agent. The forced abandonment of most of the professionals from the drug, proven as one of the most effective and mild anesthetics, provoked many protests on the part of animal lovers and pet owners, and veterinarians themselves. However, the government structures for the past ten years to their arguments and did not listen.
The composition and form of issue
The active ingredient of the drug is a NMDA-antagonist ketamine (hydrochloride). The drug is in solution intended for intravenous and intramuscular injection.
«Ketamine» available in bottles with a volume of 5 ml. In 1 ml of solution contains 250 mg of active substance. The bottle is packaged in a cardboard pack.
«Ketamine» is a means for neingalyatsionnyh anesthesia. In some cases, the drug is used as analgesic (predominantly in emergency medicine and patients who can not to assign opioid analgesics and barbiturates), as well as for the treatment of bronchospasm.
Being a non-competitive antagonist of NMDA receptors direct action (blocking the ion channel receptors), «Ketamine» can have a depressing effect on the function of neurons in the associative areas of the cerebral cortex and thalamus responsible for switching sensory impulses from the reticular activating system to the cerebral cortex.
At the same time «Ketamine» has a catalytic effect on parts of the limbic system, involved in the awareness of sensations, including the hippocampus. As a result, the patient develops functional disorganization of nonspecific links in the midbrain and thalamus (dissociative anesthesia). Clinically it is expressed as: the patient looks alert, he’s capable of, in particular, to swallow and to open the eyes, but loses the ability to analyze sensory stimuli, reacting adequately to them.
In the course of earlier research it was confirmed that «Ketamine» has the ability to bind with opioid receptors in the brain and posterior horns of the spinal cord. It is assumed that this explains the analysing effect of the drug.
A greater level of activity «Ketamine» in respect of the cortex than the thalamus, may be due to the likely uneven distribution of NMDA receptors in the Central nervous system.
After a single intravenous administration, «Ketamine» narcotic effect usually occurs within 30-60 seconds and lasts for 5-10 minutes (sometimes up to 15 minutes).
Intramuscular use of the drug in a dosage of 4-8 mg/kg «Ketamine» will take effect in 2-4 minutes (6-8 minutes). The effect lasts for 12-25 minutes (sometimes up to 40 minutes).
A pronounced analgesic effect of «Ketamine» can persist for up to two hours. After the injection, the patient is saved the pharyngeal, laryngeal and cough reflexes, the level of independent pulmonary ventilation remains adequate.
After the introduction of «Ketamine» belongs to the group of lipophilic compounds, is rapidly distributed to the organs well supplied with blood, including the brain. The tool then begins to be redistributed and in tissue with low perfusion.
The drug is metabolized in the liver. The half-life of the drug is usually two to three hours. The patient «Ketamine» leaves mainly through the kidneys in the form of conjugated metabolites.
In modern medicine, the drug «Ketamine» is used:
- for introductory and basic anesthesia in short surgical procedures, regardless of whether the muscle relaxation;
- when performing painful instrumentation, and diagnostic procedures;
- when transporting patients;
- when processing burn surface.
The dosage regimen
«Ketamine» designated doctor on an individual basis, taking into account the indications, patient’s age, clinical situation and the drugs that are used for purposes of sedation.
Intravenous administration of a single dose is usually 0.5-4.5 mg/kg to be injected into the muscle usually applied formula 4-13 mg/kg.
In patients, which is assigned to the drug «Ketamine», there may be various kinds of unwanted effects. The most common ones are:
- from the side of cardiovascular system: increased blood pressure, tachycardia;
- from the digestive system: salivation (hypersalivation);
- from the Central nervous system: psychomotor agitation, and hallucinations (when you exit the anesthesia);
- the respiratory system: shortness of breath, respiratory depression;
In extremely rare cases, there may be local reactions — soreness at the injection site and redness along the vein.
The drug «Ketamine» does not apply if the patient is diagnosed:
- violations of cerebral circulation;
- arterial hypertension;
- angina and heart failure (in the phase of decompensation);
- preeclampsia and eclampsia;
- epilepsy in childhood.
After the appointment of «Ketamine» patients are advised to refrain from driving vehicles and other potentially hazardous activities that require high level of concentration of attention and fast reactions, at least during the day.
Given the ability of «Ketamine» to cross the placental barrier and studies on the effectiveness and safety of the drug in pregnant women has not yet been conducted, the use of the drug in patients of this category are not recommended.