Analgesics, anaesthetic and sedative drugs

Question 1

Pain

Answer 1

An unpleasant sensory and emotional experience associated with actual or potential tissue damage

Question 2

Gate theory

Answer 2

C fibres let pain through

Ab fibres stimulate inhibitory neurones

Descending pathways prevent central passage

Question 3

Pain modification

Answer 3

Nociceptor C, A delta fibres

Central interpretation

Not just drugs

Question 4

Pain score

Answer 4

Linear

Smiley/ sad faces

Mild moderate severe excruciating

Question 5

Ladder

Answer 5

NSAIDS/ paracetamol

Weak opiates/ local anaesthetics

Strong opiates

Question 6

Opioids

Answer 6

Act on opioid receptor and antagonised by naxolene

Naturally occurring e.g. morphine, codeine

Semi synthetic e.g. diamorphine

Synthetic e.g. fentanyl

Weaker e.g. codeine

Question 7

Methods of administration

Answer 7

Intravenous pca/ infusion

Intramuscular

Oral

Intra nasal/ aerosol

Epidural/ spinal

Question 8

Where are receptors?

Answer 8

Pons and mid brain

Periaqueductal grey matter

Nucleus raphe magnus

Spinal cord posterior horn 1 and 2

GIT

Peripheral tissues

Question 9

Sub types

Answer 9

MU 1 and 2 OP3

Delta OP1

Kappa OP2

Question 10

Morphine

Answer 10

Effects

Side effects

Respiratory depression/ airway loss

Nausea and vomiting

Constipation/ pruritus

Miosis

Question 11

Naxolone

Answer 11

ABS

Antidote with caution

Question 12

Ketamine

Answer 12

NMDA receptors

Kappa and delta receptors

Not GABA

Analgesic local/ general

Anaesthetic

Sedative

Side effects: emergence phenomena

Question 13

NSAIDS

Answer 13

Act by inhibiting cyclooxygenase 1 and 2

Analgesic, antipyretic, anti inflammatory

Side effects

Gastric irritation

Bronchospasm

Renal impairment

Platelet function: aspirin

Question 14

Aspirin

Answer 14

Acetylsalycilic acid

Oxidative phosphorylation

Air hunger

Reyes syndrome

Question 15

Paracetamol

Answer 15

Mechanism of action? central prostaglandin effect/ unknown

Side effects

Overdose: hepatotoxicity/ glutathione depletion

N acetylcysteine

Question 16

Other analgeia

Answer 16

Anxiolysis

Local anaesthetics

Antidepressants, antiepileptics, tramadol

Guanthadine, ketamine, clonidine

Acupuncture

Inhalational nitrous oxide

Penthrox

Magnesium

Question 17

Anti emetics

Answer 17

Avoidance of emetics N2O sevoflurane

Use propofol

Cyclizine

Ondansetron

Hyoscine

Metoclopromide

Steroids

Prochlorperazine

Cannabinoids

Question 18

Ramsay sedation scale

Answer 18

Patient anxious

Cooperative

Responds only to commands

Brisk response to glabellar tap/ shout

Sluggish response

No response

Question 19

Benzodiazapines

Answer 19

Midazolam, diazepam, lorazepam

Routes of administration

Physiology

• gabba- aminobutyric acid
• inhibitory neurotransmitter
• receptors A and B

Question 20

Side effects of sedatives

Answer 20

Over sedation

Loss of airway

Respiratory depression

ABC

Flumazanyl with caution

Myth of safety, light anaesthesia

Question 21

Other sedatives

Answer 21

Low dose vapours

Ketamine

Hyoscine

Propofol low dose

Major tranquillisers

Alpha 2 agonists

Question 22

Local anaesthetic classification

Answer 22

Amides

Lignocaine, prilocaine, bupovacaine

Esters

Cocaine, amethocaine

Question 23

Local anaesthetic mechanism of action

Answer 23

Na channel blockade

Un-ionised drug through memebrane into axoplasm

Protonated

Blocks channel thus blocking action potential

Question 24

Where to put local anaesthetics

Answer 24

Spinal epidural caudal

Skin

Aerosol/ nebulised

Combination with GA

Question 25

Side effects of local anaesthetics

Answer 25

Skin/ subcutaneous

Brachial plexus

Epidural

Caudal

Intercostal

Vessels and nerves follow each other

Question 26

Toxicity

Answer 26

Cardiovascular

• dysrythmias
• cardiac depression

Central nervous sytem

• fitting/ anxiety/ loss of consciousness
• circumoral numbness

Question 27

Treatment

Answer 27

ABC

Oxygen

Lipid 20%

Dysthrythmias/ fitting