17. Anxiolytics

Question 1

General role of anxiolytic

Answer 1

alleviate fear and anxiety

Question 2

General role of sedatives

Answer 2

• alleviate fear and anxiety
• produce a degree of amnesia and analgesia

Question 3

General role of hypnotics

Answer 3

induce sleep

Question 4

Why do dentists need to know about anxiolytics-sedative-hypnotic drugs?

Answer 4

• 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

Question 5

What does the GDC think about conscious sedation?

Answer 5

• 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

Question 6

3 methods of administration in dentistry and what sedatives are admitted like this

Answer 6

• inhalation - nitrous oxide
• oral - benzodiazepines and H1 antagonists
• intravenous - benzodiazepines

Question 7

What must be used alongside a sedative?

Answer 7

• local anaesthesia
• sedation alone can’t effectievly control pain

Question 8

Difference in sedation and anaesthesia

Answer 8

• degree of unconsciousness

Question 9

Explain effect of nitrous oxide

Answer 9

• light and rapid anaesthesia
• 50% NO in oxygen - entonox
• recovery in around 4 minutes
• mild nausea and vomiting

Question 10

Negatives to nitrous oxide

Answer 10

• expensive
• limited patient groups (COPD)
• prolonged or repeated exposure causes changes to bone marrow and teratogenic risk

Question 11

How is sedative effect dose dependent?

Answer 11

• relief of anxiety
• sedation
• hypnosis
• general anaesthesia

Question 12

What is a barbiturate?

Answer 12

• positive allosteric modulator of GABAa receptors
• distinct binding site of benzodiazepines

Question 13

What do barbiturates do?

Answer 13

• direct effect on ion channel gating/opening
• increase effects of GABA and inhibit glutamate neurotransmission
• clinical use limited by increased toxicity in overdose

Question 14

3 types of anxiety disorders

Answer 14

• panic disorder
• generalised anxiety disorder
• simple phobia

Question 15

What is panic disorder?

Answer 15

discrete periods of intense fear

Question 16

What is generalised anxiety disorder?

Answer 16

chronic worry

Question 17

What is simple phobia?

Answer 17

fear of object or situation

Question 18

What treats anxiety disorders?

Answer 18

benzodiazepines

Question 19

Pharmacological effects of benzodiazepines

Answer 19

• reduction of anxiety and aggression
• sedation and induction of sleep
• muscle relaxation
• anticonvulsant effects
• amnesia

Question 20

How do benzodiazepines sedate and induce sleep?

Answer 20

• decrease time taken to get to sleep
• increase total duration of sleep
• decrease REM sleep (dreaming)
• decrease SW sleep (deep sleep)

Question 21

How do benzodiazepines cause muscle relaxation?

Answer 21

• increased muscle tone usually in anxious people
• may cause aches and pains like headache
• relaxant effect so clinically useful

Question 22

Mode of action of benzodiazepines

Answer 22

• 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

Question 23

Pharmacokinetics of benzodiazepines

Answer 23

• 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

Question 24

Why are some benzos short acting?

Answer 24

• metabolised to inactive compounds
• short half life e.g temazepam

Question 25

Why are some benzos long acting?

Answer 25

• 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

Question 26

Which benzo goes straight to glucuronide?

Answer 26

lorazepam

Question 27

Which benzos become hydroxylated metabolites before glucuronide?

Answer 27

• triazolam
• alprazolam
• midrazolam
• clonazepam

Question 28

Unwanted effects of benzos

Answer 28

• interacts with alcohol
• long lasting ‘hangover effects’ e.g drowsiness, confusion
• development of dependence
• sexual fantasies

Question 29

Why can benzos be used in suicide attempters?

Answer 29

• reasonably safe in overdose

Question 30

How do benzos act in dentistry?

Answer 30

• ensure undisturbed sleep before a dental appointment
• sedation as adjunct to local anaesthesia - amnesia
• pre-anaesthetic medication (anti-anxiolytic)

Question 31

What do beta-adrenoceptor antagonists do?

Answer 31

• anxiolytic but not sedative - reduce physcial symptoms like tremor, palpitations
• inhibit somatic or autonomic responses - decreases noradrenergic transmission

Question 32

Example of a beta-adrenoreceptor antagonist

Answer 32

• propranolol

Question 33

Unwanted side effects of beta-adrenoceptor antagonists

Answer 33

• cardiac depression, bradycardia
• non-selective beta-adrenoceptor inhibition (beta1/beta 2)

Question 34

What do 5-HT1a agonists do ?

Answer 34

• anxiolytic but not sedative - partial agonist of inhibitory autoreceptors (5-HT1A)
• long anxiolytic development time - over 2 weeks

Question 35

Example of a 5-HT1a agonist

Answer 35

buspirone

Question 36

Do 5-HT1a agonists have lots of withdrawal effects?

Answer 36

• no
• generally mild nausea and dizziness but not much