17. Anxiolytics Flashcards
(36 cards)
1
Q
General role of anxiolytic
A
alleviate fear and anxiety
2
Q
General role of sedatives
A
- alleviate fear and anxiety
- produce a degree of amnesia and analgesia
3
Q
General role of hypnotics
A
induce sleep
4
Q
Why do dentists need to know about anxiolytics-sedative-hypnotic drugs?
A
- administered to patients who can’t handle emotional stress of the dentists
- like in anxiety (feeling uneasy, palpitations, sweating, tense muscles, headache)
- some patients may need sedation
5
Q
What does the GDC think about conscious sedation?
A
- can be effective method of facilitating dental treatment
- produces a state of depression of the CNS
- verbal contact with patient is maintained
- deep sedation … must be regarded as general anaesthesia
- patient … is able to understand and respond to verbal commands
6
Q
3 methods of administration in dentistry and what sedatives are admitted like this
A
- inhalation - nitrous oxide
- oral - benzodiazepines and H1 antagonists
- intravenous - benzodiazepines
7
Q
What must be used alongside a sedative?
A
- local anaesthesia
- sedation alone can’t effectievly control pain
8
Q
Difference in sedation and anaesthesia
A
- degree of unconsciousness
9
Q
Explain effect of nitrous oxide
A
- light and rapid anaesthesia
- 50% NO in oxygen - entonox
- recovery in around 4 minutes
- mild nausea and vomiting
10
Q
Negatives to nitrous oxide
A
- expensive
- limited patient groups (COPD)
- prolonged or repeated exposure causes changes to bone marrow and teratogenic risk
11
Q
How is sedative effect dose dependent?
A
- relief of anxiety
- sedation
- hypnosis
- general anaesthesia
12
Q
What is a barbiturate?
A
- positive allosteric modulator of GABAa receptors
- distinct binding site of benzodiazepines
13
Q
What do barbiturates do?
A
- direct effect on ion channel gating/opening
- increase effects of GABA and inhibit glutamate neurotransmission
- clinical use limited by increased toxicity in overdose
14
Q
3 types of anxiety disorders
A
- panic disorder
- generalised anxiety disorder
- simple phobia
15
Q
What is panic disorder?
A
discrete periods of intense fear
16
Q
What is generalised anxiety disorder?
A
chronic worry
17
Q
What is simple phobia?
A
fear of object or situation
18
Q
What treats anxiety disorders?
A
benzodiazepines
19
Q
Pharmacological effects of benzodiazepines
A
- reduction of anxiety and aggression
- sedation and induction of sleep
- muscle relaxation
- anticonvulsant effects
- amnesia
20
Q
How do benzodiazepines sedate and induce sleep?
A
- decrease time taken to get to sleep
- increase total duration of sleep
- decrease REM sleep (dreaming)
- decrease SW sleep (deep sleep)
21
Q
How do benzodiazepines cause muscle relaxation?
A
- increased muscle tone usually in anxious people
- may cause aches and pains like headache
- relaxant effect so clinically useful
22
Q
Mode of action of benzodiazepines
A
- benzos act by binding to specific regulatory site of GABAa receptor
- this binding enhances neuronal inhibitory effect of GABA
- GABA and benzo bind to independent sites of same receptor-Cl-ion channel complex
- benzo don’t open Cl-ion channel by themselves, just increase the affinity for receptor for GABA
23
Q
Pharmacokinetics of benzodiazepines
A
- well absorbed when given orally
- binds strongly to plasma proteins
- high lipid solubility leads to accumulation in body fat
- inactivated by metabolism and excreted as glucoronides in urine
- varys on action length
24
Q
Why are some benzos short acting?
A
- metabolised to inactive compounds
- short half life e.g temazepam
25
Why are some benzos long acting?
- metabolised to pharmacologically active metabolites with long half lives
- diazepam is metabolised to noridazepam which has a half life of around 60 hrs for example
26
Which benzo goes straight to glucuronide?
lorazepam
27
Which benzos become hydroxylated metabolites before glucuronide?
- triazolam
- alprazolam
- midrazolam
- clonazepam
28
Unwanted effects of benzos
- interacts with alcohol
- long lasting 'hangover effects' e.g drowsiness, confusion
- development of dependence
- sexual fantasies
29
Why can benzos be used in suicide attempters?
- reasonably safe in overdose
30
How do benzos act in dentistry?
- ensure undisturbed sleep before a dental appointment
- sedation as adjunct to local anaesthesia - amnesia
- pre-anaesthetic medication (anti-anxiolytic)
31
What do beta-adrenoceptor antagonists do?
- anxiolytic but not sedative - reduce physcial symptoms like tremor, palpitations
- inhibit somatic or autonomic responses - decreases noradrenergic transmission
32
Example of a beta-adrenoreceptor antagonist
- propranolol
33
Unwanted side effects of beta-adrenoceptor antagonists
- cardiac depression, bradycardia
- non-selective beta-adrenoceptor inhibition (beta1/beta 2)
34
What do 5-HT1a agonists do ?
- anxiolytic but not sedative - partial agonist of inhibitory autoreceptors (5-HT1A)
- long anxiolytic development time - over 2 weeks
35
Example of a 5-HT1a agonist
buspirone
36
Do 5-HT1a agonists have lots of withdrawal effects?
- no
- generally mild nausea and dizziness but not much
