Anxiolytics And Hypnotics Flashcards
(27 cards)
Treating anxiety disorders
- CBT
- Applied relaxation
- Medication ( Anxiolytics and hypnotics )
Anxiolytics
Used to treat anxiety disorders
Hypnotics
Used to treat insomnia
Types of insomnia
- Transient (jet lag)
- Short term (illness or stress)
- Chronic (alcohol or drug misuse or dependence)
What type of drugs are anxiolytics and hypnotics
CNS depressant drugs
Therapeutic window of CNS depressants
Low dose - Anxiolytics High dose - Hypnotics ( sedative effect - induce sleep ) Anaesthesia Toxic dose - coma Respiratory depression
What are barbiturates?
- GABAa receptor modulators
- Positive allosteric modulators
- Severe CNS depressants
- Used in treatment of epilepsy, general anaesthesia and capital punishment
- no longer used as anxiety treatment
- Are dirty compounds having other actions at high doses
How do barbiturates work?
- Bind to GABA A receptor
- Channel is opened more than if GABA bound alone
- Enhances function response
- Increases activity of GABA A receptor
Effects of barbiturates at high doses
- Direct GABA A agonise
- nAchR and 5-HT3 blockade
- AMPA and Kainate blockade
- Blockade of calcium dependent neurotransmitter release
- Stabilise open channel of glycine receptor
What are benzodiazepines?
- GABA A receptor modulators
- Decrease anxiety and induce sleep
- reduction in muscle tone and anticonvulsant effects
- Specific to GABA A receptor so lower dose required
- Antidote available to reduce effects of bzd e.g. flumenazil
- short acting drug so avoid sedative effects during the day
How do benzodiazepines work?
- Stabilise GABA A receptor binding site for GABA in open configuration
- Increases GABA affinity for its binding site
Only bind to alpha 1, 2, 3 or 5
- BZD bind at alpha gamma interface
Side effects of benzodiazepines
- Drowsiness
- Confusion
- Forgetfulness
- Loss of motor control
- Combined with alcohol causes respiratory depression
What are Z Drugs
- Hypnotics only
- GABA A Modulators
- Act on benzodiazepine binding site
- Structurally different time bzd - bzd have Cl attached to aromatic ring
GABA A receptors
- inhibitory effects
- Ligand gated Cl- channel
- Causes hyperpolarisation
- GABA binds at alpha beta interface
How is addiction to benzodiazepines caused?
- ) More glutamate receptors than GABA
- ) Benzodiazepines restore balance between GABA and glutamate
- ) Body develops tolerance to drug and neuroadaptation takes place
- ) More glutamate receptors are trafficked leading back to imbalance
- ) Withdrawal from drug causes severe lack of GABA
Using benzodiazepine to treat alcohol dependence
- ) Balance between glutamate and GABA activity in healthy person
- ) More GABA activity in an alcoholic
- ) Withdrawal from alcohol causes neuroadaptation where more glutamate receptors are trafficked
- ) Benzodiazepine restores imbalance between GABA and glutamate
What is a 5-HT1A agonist?
- metabotropic (GPCR)
- Used to treat GAD e.g. buspirone
- Less tolerance and withdrawal symptoms
- Does not induce sleep
How do 5-HT1A agonists work?
- Activate pre-synaptic 5-HT1A autoreceptots
- are auto inhibitory and initially decrease serotonin levels
- Induce desensitisation of 5-HT1A autoreceptor causing enhanced release of serotonin in the long term
- Reduces noradrenergic neuron activity and decreases arousal
What are beta adrenoceptor antagonists?
- Treat some forms of anxiety e.g. propranolol
- Metabotropic receptor (GPCR)
- Reduce some of the peripheral manifestations of anxiety and do not have an effect on CNS
What does beta-1 and beta-2 do?
Beta 1 increases heart rate, contraction and ejection fraction
Beta 1 and 2 increases renin release by juxtaglomerular cells
What are antihistamines?
- used to treat allergic conditions e.g. hay fever
- found in some cold remedies
- only hypnotics due to sedative effect
How do antihistamines work?
Histamine H1 receptor are responsible for wakefulness
- Using antihistamines overcome this
Benzodiazepine drug examples
- Lorazepam
- Temazepam
- Clonazepam
Z Drug examples
- Zolpidem
- Zopiclone
