PHAR 100 - Module 3 Flashcards
sedative-hypnotics and anxiolytics
- are CNS depressants
- decrease glutamate-induced nerve firing
GABA signalling
- primary inhibitory neurotransmitter in the CNS
- causes inhibition by binding to and selectively opening chloride channels, resulting in hyperpolarization of the post-synaptic membrane of a neuron
- overall effect is that it is harder for the post-synaptic neuron to transmit incoming messages to other neurons, depressing overall CNS neuronal signalling
drugs that bind to the chloride channel
- most sedative-hypnotics:
- modulate the chloride ion channel in the brain and spinal cord
- result is an increase in synaptic inhibition and thus a dampening of neuronal 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
benzodiazepine routes of admin
capsule, tablet or IV
benzodiazepine lethality
- commonly involved in overdoses
benzodiazepine pharmacological processes
- very high therapeutic index
- some members of this group are effective hypnotics
benzodiazepine short-term use
- CNS → relaxation, calmness, anxiety relief
- lung → respiratory depression
- motor coordination → can impair motor coordination
benzodiazepine long-term use
- impaired thinking, poor memory
- disorientation
- slurred speech
benzodiazepine abuse potential
- low abuse liability
- low inherent harmfulness
- margin of safety is high
benzodiazepine dependence
- tolerance → can develop to sedative effects; high degree of cross-tolerance occurs among other sedative-hypnotics
- dependence → low for short term use
- addiction → may develop for some
barbiturates
- potent CNS depressants
barbiturates mechanism of action
activation of the barbiturate receptor increases the duration of the opening of the chloride channel
barbiturates pharmacology
- possess a low therapeutic index
- suppress REM sleep
- depress respiratory system
barbiturates short-term effects
- mild euphoria
- dizziness
- sleep
barbiturates long-term effects
chronic inebriation
barbiturates abuse potential
- abuse liability is equal to or greater than alcohol
- inherent harmfulness is high due to risk of death from respiratory depression
barbiturates dependence
- tolerance → can develop to sleep induction and mood effects
- dependence → a withdrawal syndrome occurs (tremors, anxiety, insomnia, seizures, hallucinations)
- addiction → can result from regular use
flumazenil
- a benzodiazepine receptor antagonist that blocks the effect of benzodiazepines
- can be used as an antidote to benzodiazepine overdose
zolpidem
- bind to a subset of the GABA receptors, causing sedation
- disturb sleep less than benzodiazepines
buspirone
- acts at the serotonin receptor
- used in generalized anxiety states
- doesn’t have an addictive effect