3.1 Sedative-Hypotonics And Anxiolytics Flashcards
Sedated-hypnotic agents
- CNS depressants
- Magnitude of CNS depression produced by a drug at a particular dose determines what effect the agent produces
Antianxiety
-Are used to treat anxiety disorders, such as generalized anxiety disorder obsessive compulsive disorder
Sedation
-Used to relieve anxiety, decreased activity, moderate excitement, and generally, the individual
Hypnosis (sleep)
-Used to produce drowsiness and eight in the onset and maintenance of sleep
General anaesthesia
-Used to induce general anesthesia, which is a state of unconsciousness with an absence of pain sensation
Controlling CNS excitation
- glutamate is the major excitatory neurotransmitter in the brain
- when a person is anxious or having difficulty sleeping, therapies and depressed overall brain activity, decreasing glutamate induced nerve firing
- can be done by increasing inhibitory signalling in the brain
Drug classes
- class of drugs is a group of drugs with the same mechanism of action and similar pharmacological properties
- Thiopental secobarbital and phenobarbital are all drugs that ponder the barbiturate class of drugs
How to increase inhibitory signalling in the brain
- Most brain activity involves excitatory neurons these release the neurotransmitter glutamate neurons fire when the excitatory input exceed inhibitory inputs
- Inhibitory signals from GABA Neurons increase with the most sedative hypnotics
- Increase and GABA Ronald firing results in decreased glutamate nerve firing
GABA Signalling
- GABA is the primary inhibitory neurotransmitter in the CNS
- It causes inhibition by binding to an selectively opening chloride channels, resulting in hyper polarization of the postsynaptic membrane of a neuron
- Effective that is harder for the postsynaptic neuron to transmit incoming messages to other neurons, depressing overall CNS neuronal signalling
Drugs that bind the chloride channel
- most sedative hypnotics modulate the chloride ion channel in the brain and spinal cord, but each binding to a different site on the chloride channel
- result is an increase in synaptic inhibition and thus a dampening of neuron responses in essence they enhance the inhibitory effect of GABA
Benzodiazepines Mechanism of action
- ## activation of the Benzodiazepine receptor increases the frequency of the opening of the chloride channel
Route of administration benzodiazepines
-Benzodiazepines are usually taken as a capsule or tablet, but some are available for intravenous use
Lethality benzodiazepines
- most commonly involved in overdose
- wide margin of safety means death from overdose are rare
- deaths occurred following injection of Enormous doses, rapid intravenous injection of a large dose, or when a large dose was taken in combination with other drugs like alcohol
Pharmacological properties of the benzodiazepines
- they possess a very high therapeutic index
- they produce antianxiety effects, sedation and amnesia
- they can decrease aggression
- some members of this group are effective hypnotics (drowsiness, facilitates onset and maintenance of sleep)
- they produce minimal suppression of rapid eye movement REM type sleep with hypnotic benzodiazepines (flurazepam) at normal doses
- they produce skeletal muscle relaxation (Diazepam)
- they have anti-convulsant action (diazepam)
- an antidote exist to reverse it’s effects in the case of an overdose (flumazenil)
Effects of benzodiazepine short term use
- cns
- lungs
- motor coordination
Short term use cns
The desirable affects our relaxation, calmness, and relief from anxiety or tension. Other effects may include drowsiness, lethargy, fatigue, and impairment of thinking and memory
Short term use on lungs
-respiratory depression has been observed following rapid intravenous administration