Benzodiazepines and use in IV sedation

Question 1

Common examples

Answer 1

Midazolam
Temazepam
Diazepam

Question 2

Side effects of BZD

Answer 2

Respiratory depression
CNS depression
Muscle relaxation
Reduced BP, Increased HR = same CO
Drug interactions - opiates and alcohol

Question 3

Drug interactions with BZDs

Answer 3

1) H2 receptor blockers and erythromycin - inhibits BZD metabolism
2) Muscle relaxants - enhanced effect
3) Antihypertensives - hypotension
4) Antipsychotics - enhanced effect
5) Antifungals - inhibit metabolism of BZDs

Question 4

Mechanism of BZDs

Answer 4

GABA agonists
Bind to 𝛾-sub units
Alter structure of receptors
Potentiate effect of GABA - chloride ion influx
Reduced excitability and potentiation of nerve impulses

Question 5

Effects of BZDs

Answer 5

Anxiolysis
Sedation
Anticonvulsant
Amnesiac
Muscle relaxant

Question 6

As % BL

Effects of BZDs

Answer 6

<20% = anxiolysis
30-50% = sedation
60%+ = anaesthesia

Question 7

Half life of a drug is

Answer 7

The time for serum concentration/metabolism of 1/2 drug

Question 8

Diazepam routes of administration

Answer 8

Oral, IV, transmucosal

Question 9

2 metabolites

Diazepam has -

half lives of each

Answer 9

Oxazepam 73 +/-33h
Desmethyldiazepine 6.3 +/- 1.3h

Question 10

Diazepam has a rebound sedation risk of

Answer 10

4-6 hours after administration

Question 11

Temazepam properties

Answer 11

Rapid acting 20-30 min
10-20mg tabs or 10mg/5ml elixir
Half life of 13 +/- 3h
Inactive metabolites
CDIII

Question 12

Midazolam chemical factors

Answer 12

2-3x more potent than diazepam
Water soluble pH <4
Lipid soluble at body pH

Question 13

Midazolam action and dosage versions

Answer 13

20-30s time to reach blood-brain barrier
5mg/5ml, 10mg/2ml, 10mg/5ml

Question 14

Midazolam 1/2 life and metabolites

Answer 14

Alpha half life 15-30 mins
Beta elimination 1/2 life 1.9h +/- 0.9h
1,4-hydroxymidazolam 1.25h +/- 0.25h

Question 15

Midazolam routes of admin

Answer 15

Oral, buccal, transmucosal, IV, rectal

Question 16

Midazolam in a medical emergency

Answer 16

10mg buccal for epileptic seizure

Question 17

Midazolam risk of rebound sedation

Answer 17

Only if interacting with other drugs or reversal agent

Question 18

Midazolam in older people

Answer 18

Metabolism time increases with age

Question 19

Advantages of midazolam

Answer 19

Fast onset
Shorter half life
Faster recovery
Less painful injection

Question 20

Midazolam indications

Answer 20

Anxiety
ASA I-II
Overactive gag reflex
Involuntary movements e.g. cerebral palsy/Parkinsons/Tourette’s
Mild learning difficulty
Prolonged surgical procedures
Where RA is not suitable - nasal obstruction/claustrophobia

Question 21

Midazolam contraindications

Answer 21

Uncontrolled respiratory diseases
Severe/uncontrolled comorbidities
Poor co-operation
Severe learning difficulties
BMI > 40
Pregnancy
Children < 12
Severe needle phobia
Procedure requiring more than LA

Question 22

Flumazenil type of drug and chemical feature

Answer 22

BZD antagonist
No benzene ring
Displaces bound BZD from receptor
High affinity for receptors therefore blocks effect of BZD

Question 23

Flumazenil:
Route
1/2 life - alpha and beta
Dosage
Ampules required for an IV sedation session

Answer 23

IV only
7-15 mins and 50-53 mins
Dose is 500 µg/5ml
200µg/15 s then 100µg/60s and observe effect up to 1g/2amps
2 ampules (1g) + spare ampule

Question 24

Flumazenil risks and contraindications

Answer 24

Does not affect metabolism of midazolam
Short half life and risk of resedation with midazolam
Known epileptics with BZD use as may cause convulsions
Hypersensitivity to BZ as flumazenil will potentiate this

Question 25

Signs of sedation

Answer 25

Slurred speech
Muscle relaxation
Ptosis (over)
Delayed response to stimuli
Verbal contact maintained

Question 26

Complications of sedation

Answer 26

Respiratory depression
Hypotension
LoC
Airway obstruction
Allergic reaction

Question 27

Titration of a drug is

Answer 27

Addition of small increments to observe clinical response of physiological changes

Question 28

5mg/5ml midazolam is given

Answer 28

in 0.5ml-1ml increments

Question 29

Discharge of patient involves observation of

Answer 29

-ve Eve and Rhomberg sign
Restoration of proprioception, vestibular fx and vision
BP and PPO2 to baseline

Question 30

Alpha half life

Answer 30

Time for serum concentration of a drug to reduce by 50%

Question 31

Beta half life

Answer 31

Time for 50% of a drug to be eliminated via metabolism

Question 32

Diazepam

Diazepam half lives
Alpha
Beta
Dose

Answer 32

40 minutes
43 hours
0.1-0.2 mg/kg