Pain Management

Question 1

Define Pain

Answer 1

An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage

Question 2

What are the two broad distinctions of pain?

Answer 2

Acute

Chronic

Question 3

What are the four distinctions of chronic pain?

Answer 3

Nociceptive
Neuropathic
Visceral
Mixed

Question 4

What are the two distinctions of neuropathic pain?

Answer 4

Central

Peripheral

Question 5

Give examples of acute pain

Answer 5

Trauma

Post-op flare

Question 6

Give examples of nociceptive pain

Answer 6

Osteoarthritis

Rheumatoid arthritis

Question 7

Give examples of central neuropathic pain

Answer 7

Post-stroke
MS
Spinal cord injury
Migraine
HIV related neuropathic pain

Question 8

Give examples of peripheral neuropathic pain

Answer 8

Post-hepatic neuralgia

Diabetic neuropathy

Question 9

Give examples of visceral pain

Answer 9

Internal organ pain
Pancreatitis
IBS

Question 10

Give examples of mixed pain

Answer 10

Lower back pain
Cancer
Fibromyalgia

Question 11

What are the goals of pain management?

Answer 11

Minimise stress response/neuroendocrine effects
Minimise adverse effects on wider systems
Patient comfort and satisfaction

Question 12

What are the three stages of the WHO pain ladder?

Answer 12

Step 1 - simple analgesics (aspirin/paracetamol)
Step 2 - opioids (mod pain) + simple analgesics
Step 3 - opioids (sev pain) + simple analgesics

Question 13

How does Paracetamol work?

Answer 13

MoA uncertain

Question 14

What are the two main actions of Paracetamol?

Answer 14

Analgesia

Antipyretic

Question 15

What formulations is Paracetamol available in?

Answer 15

Tablets (+ soluble)
Capsules
Suspension
Suppository
Infusion

Question 16

What are the major problems with Paracetamol?

Answer 16

Side effects uncommon

Overdose common - liver damage (14 tabs)

Question 17

What is the treatment for Paracetamol overdose?

Answer 17

Acetylcysteine

Question 18

How do NSAIDs work?

Answer 18

Inhibit COX - prevent formation of prostaglandins/thromboxanes

Question 19

What are the three main actions of NSAIDs?

Answer 19

Analgesia
Antipyretic
Anti-inflammatory

Question 20

What formulations are NSAIDs available in?

Answer 20

Tablets (+ soluble)
Capsules
Suspension
Suppository
Creams
Gel
Patch
Infusion

Question 21

What are the major GI adverse effects of NSAIDs?

Answer 21

GIT erosion & ulceration

Question 22

What are the major renal adverse effects of NSAIDs?

Answer 22

Reduce renal blood flow - acute failure

Na/K/H2O retention

Question 23

What are the major respiratory adverse effects of NSAIDs?

Answer 23

Bronchospasm

Question 24

What are the major haematological adverse effects of NSAIDs?

Answer 24

Reduce platelet aggregation

• Aspirin irreversible
• NSAIDs reversible

Question 25

How should NSAIDs generally be used?

Answer 25

Lowest effective dose Shortest period of time possible Co-prescription of a PPI

Question 26

What are the clinically common weak opioids?

Answer 26

Codeine Dihydrocodeine Dextropropoxyphene Tramadol (po)

Question 27

What are the clinically common strong opioids?

Answer 27

``` Morphine Diamorphine Oxycodone Buprenorphine Fentanyl ```

Question 28

When are weak opioids most effective?

Answer 28

When used in combination with paracetamol

Question 29

What CYP450 protein is responsible for the metabolism of Codeine-Morphine?

Answer 29

CYP450 2D6

Question 30

What populations are unable to metabolise Codeine-Morphine?

Answer 30

10% caucasian | 90% chinese

Question 31

When are strong opioids used?

Answer 31

Acute pain Persistent non-cancer pain Palliative care

Question 32

What is the ceiling effect?

Answer 32

The point at which increasing dose does not increase analgesia

Question 33

What type of painkiller does not have a ceiling effect?

Answer 33

Strong opioids

Question 34

What routes of administration are available for strong opioids?

Answer 34

``` Oral Rectal Transdermal Sublingual Topical Intramuscular Subcutaneous Intravenous Epidural Intrathecal ```

Question 35

What are the major adverse effects of opioids?

Answer 35

``` Nausea & Vomiting Constipation Sedation Respiratory depression Hypotension Urinary retention ```

Question 36

What are the three steps taken when initiating morphine treatment?

Answer 36

Pain assessment Determine opioid requirement Convert daily dose to MR formulation

Question 37

What is breakthrough pain?

Answer 37

Transient exacerbation/recurrence of pain in a mainly stable patient

Question 38

When does breakthrough pain commonly occur?

Answer 38

End of dose failure Incident pain Spontaneous, unpredictable pain

Question 39

How do you control breakthrough pain?

Answer 39

Add 10% total daily regular dose prn

Question 40

Describe the treatment structure with i.m. opioids

Answer 40

4 hourly Several doses to achieve adequate levels Variable absorption Painful

Question 41

What is the preferred drug for Patient Controlled Analgesia?

Answer 41

Morphine i.v.

Question 42

What drugs can be prescribed for PCA if the patient has an allergy to Morphine?

Answer 42

Tramadol Oxycodone Fentanyl

Question 43

What are the advantages of PCA?

Answer 43

``` Rapid analgesia Ready prepared Patient satisfaction No dose delay No peaks/troughs ```

Question 44

What are the disadvantages of PCA?

Answer 44

Expensive i.v. Training Monitoring

Question 45

Describe epidural opioids

Answer 45

Alternative to PCA | Mixture of local anaesthetic and opioid

Question 46

What are the major adverse effects of epidural opioids?

Answer 46

Hypotension Infection 'wrong route'

Question 47

What is the most common epidural opioid preperation?

Answer 47

Fentanyl w/ (levo)bupivicaine

Question 48

Describe syringe drivers

Answer 48

Continuous subcutaneous infections

Question 49

When are syringe drivers indicated?

Answer 49

Unable to take medicines by mouth | Bowel obstruction

Question 50

What is the most common opioid used in syringe drivers, and why?

Answer 50

Diamorphine | Excellent aqueous solubility

Question 51

What parameters should be monitored when treating with opioid?

Answer 51

``` Pulse BP Resp rate Ox saturation Pain intensity Sedation score Opioid usage/side effects ```

Question 52

How does Tramadol work?

Answer 52

u agonist | Inhibits NA uptake/5-HT

Question 53

What is the side effect profile of Tramadol?

Answer 53

Less opioid side effects | Nausea/hallucinations

Question 54

How is Tramadol absorbed?

Answer 54

70% absorbed po | Peak 2 hrs

Question 55

How does Naloxone work?

Answer 55

Opioid antagonist --> reverses effects of opioids

Question 56

How should Naloxone treatment be structured?

Answer 56

Repeated doses given i.v. (short half life) Gradual titration -May induce pain

Question 57

What is the typical cause of neuropathic pain?

Answer 57

Damage/lesion somewhere between a peripheral nerve and the brain

Question 58

What are the symptoms of neuropathic pain?

Answer 58

``` Burning Electric shock Pins/needles Scalding Shooting Stabbing ```

Question 59

What are the signs of neuropathic pain?

Answer 59

Continous pain Evoked pain -Hyperalgesia -Allodynia

Question 60

What are the pharmacological treatments for neuropathic pain?

Answer 60

``` TCAs Anticonvulsants Opioids Local anaesthetics Capsaicin ```

Question 61

How do TCAs work?

Answer 61

Inhibit NA/serotonin reuptake

Question 62

What limits the use of TCAs?

Answer 62

Widespread adverse effects

Question 63

What are the two most clinically common anticonvulsants?

Answer 63

Gabapentin | Pregabalin

Question 64

How do anticonvulsants work?

Answer 64

Prevent voltage dependent Ca channel activation in dorsal horn neurones