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Flashcards in Pain Deck (66)
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1

What is pain

Unpleasant sensory and emotional experience
Associated with actual or potential tissue damage

2

What are simple analgesics

Paracetamol
NSAID

3

What are opioids

Codeine
Dihydrocodeine
Co-codomol (8/500 or 30/500) or codydramol
Morphine
Oxycodone
Fetanyl

4

What are other options for pain relief

Tramadol - small opiate + 5HT / NA reuptake inhibitor
TCA
Anti-convulsants
Ketamine - NMDA receptor antagonist
LA
Nerve block
Spinal and epidural
Topical - capsaicin

5

Action of paracetamol

Inhibits prostaglandin synthesis

6

What is it good for

Mild pain
Very effective with NSAID
Severe pain in combination with other drugs

7

SE

Almost none
Very cheap and safe
Liver damage in overdose so caution in impairment

8

How is it given

Oral
Rectal
IV - adjust dose according to weight

9

Action of NSAID (Ibuprofen / Aspirin / Diclofenac)

Inhibit enzyme cyclo-oxygenase which is used in prostaglandin and thromboxane synthesis

10

What are NSAID good for

Nociceptive pain
In combination with paracetamol

11

When do you have caution with NSAID

GI pathology - peptic ulcer
Bleeding / anti-coagulation
Impaired renal
Sensitive asthmatics
Elderly
Aspirin CI in children due to risk of Reye's

12

What do opioids do and how do you give

Act peripherally and centrally at opioid receptor to inhibit transmission off pain (analgesia)
Can give by all route but must convert dose

13

What are the SE of opioids

Resp depression as decreased sensitivity to CO2
N+V so give with anti-emetic
Constipation - decreased motility
Miosis

Other
Headache
Urinary retention
Bradycardia
Hallucination
Sedation

Release of Histamine
- Bronchospasm
- Hypotension (vasodilation)
- Itch and wheels
- Phlebitis

Endocrine
- Inhibition of ACTH / prolactin / FSH / LH
- Increased ADH

14

Why are opioids controlled drugs

Due to addictive nature
Risk of tolerance and dependence

15

What is morphine useful for

Moderate - severe acute nociceptive pain I.e. hip fracture
Give 10mg IV
Chronic cancer pain

16

What are disadvantages of morphine

Significant first pass metabolism
COnstipation
Resp depresion
Addiciton

17

What should oral dose of morphine be compared to IV

3x larger

18

What is codeine good for

Mild-moderate acute nociceptive pain
Best given regularly with paracetamol

19

What is codeine not good for

Chronic pain
Cause constipation

20

What is tramadol and how does it act

Weak opioid plus inhibitor of serotonin and Na reputake
Acts at spinal cord to dampen pain transmission

21

Benefits of tramadol

Less resp depression
Can be used with other opioids and simple analgesia
Not a controlled drug - now controlled

22

When do you use

NO justification as first line unless other opioid CI

23

Disadvantages

N+V
Caution in epilepsy as lower seizure
Caution if use with TCA / SSRI as lower seizure

24

How does amitriptyline (TCA) work

Increases descending inhibitory signals

25

What is it good for

Neuropathic pain
Depression / poor sleep

26

Disadvantages

Anti-cholinergic SE
- Glaucoma
- Urinary retention so do not give if BPH
- CI MG

27

What anti-convulsants are useful for pain and what role

Gabapentin / Pregabalin = 1st line
Carbamazepine
Sodium valproate

Membrane stabiliser so reduce abnormal firing of nerves
Good for neuropathic pain

28

What are 4 steps of pain transmission

Periphery
Spinal Cord
Brain
Modulation

29

What happens at periphery

Tissue injury
Release of prostaglandin / substance P
Stimulation of pain receptors
Signal travel in nerves

30

What nerves carry pain

A delta
C