Liquid Ketamine is a multifunctional drug that starts as an anesthetic agent and is now used for pain relief and anti-depression. Along with this, it is also used to make one relax and entertain. Being a lipophilic agent it enters the brain quickly and has distribution to other organs.
History: It was made in 1962 having a developmental code name of Cl-581 and was added to prescriptions in the United States in 1970.
Structure: Belongs to the class of cyclohexanones and is an arylcyclohexylamine derivative.
Belongs to: It is a short-acting, nonbarbiturate anesthetic, that induces a state in which the patient is unconscious and does not feel pain.
What is a dissociative state?
This is a state produced by ketamine in which there is a partial loss of memory, sedation, and immobility.
Depending on the dose, it acts on different receptors when a high dose is given it acts on sigma and opioid mu receptors which results in analgesia and euphoria. Mainly acts as an antagonist on N-Methyl-D-aspartate receptors which are glutamate-gated cation channels having a very important role in synaptic function in the brain. Due to NMDA receptor antagonism, there is a hindrance in pain transmission in the spinal cord. For antidepressive effect with NMDA receptor antagonism, there will be activation of AMPA receptors leading to an impact on neurotransmission in the limbic system.
Doses and effects:
To have analgesic and antidepressive effects plasma concentration of 70 to 200 ng/ml is required. For anesthesia, it depends upon either being administered alone or in combination. If given with midazolam dose will be 0.5 to 2 mg/kg and alone it will be 1 to 4.5 mg/dl.
Injectables: 10 mg/ml, 50 mg/ml and 100 mg/ml.
Resistant depression: 0.5 to 1 mg/ml IV.
Distribution and metabolism:
Due to its lipid-soluble property, it has an extensive distribution and the amount that enters circulation depends upon the route of drug administration. Intravenous administration has the highest bioavailability than intramuscular injection which has an 85 to 95 percent distribution rate and the lowest rate is via the oral route due to the first-pass effect which involves metabolization of drugs mostly in the liver.
- Being a recreational agent used to make one relax and have good feelings for some time.
- Beneficial to use in asthmatic patients as it leads to bronchodilation.
- Helpful in cardiogenic shock as a stimulator of central sympathetic outflow leads to stimulation of the cardiovascular system causing increased cardiac output and blood pressure.
- Due to its safety and short-acting properties used mainly in children and elderly adults for short procedures.
- Being a rapid-acting antidepressant used for the treatment of treatment-resistant depression.
- Being strong analgesic property and low dose as compared to anesthetic dose it is used to relieve pain during surgery.
- Due to its short and rapid-acting property, it is a drug of choice for small procedures.
- When given in anesthetic doses it leads to stimulation of the circulatory system.
- As compared to other anesthetics, it has a positive effect on the respiratory system.
- Safe to use in children having congenital cyanotic heart disease.
- Safe to use in chronic obstructive airway diseases like emphysema etc.
- Due to its positive effect on the heart, it is a drug of choice in traumatic patients having hypotension.
- Have a positive effect on patients having multiple episodes of seizures with no consciousness between episodes.
- As it leads to stimulation of the sympathetic nervous system so not used in patients having raised intracranial and intraocular pressure.
- Having a positive effect on the circulatory system causes devastating effects in the case of poorly controlled hypertension and unstable angina.
- Not to use in pregnancy as it crosses the blood-placental barrier leading to neuro-toxicity to the fetal brain.
- Chronic use might lead to kidney failure.
- Has the ability to develop dependence and tolerance.
Having more positive effects as compared to negative effects it is safe to use and has more efficacy than other drugs in this class. Well, that was all. Hopefully, this brief article will help you a lot.