Pain Management - Nociceptive

Question 1

WHO Analgesic Ladder

Answer 1

Mild/moderate
-paracetamol
+NSAID

Moderate/severe
-paracetamol
+NSAID
+weak opioid

Severe
-paracetamol
+NSAID
+strong opioid

Question 2

Paracetamol

• MOA
• SE
• CI, warnings
• max dose

Answer 2

Analgesia - inhibit prostaglandin synth
Antipyretic - acts on hypothalamic temp sensors => peripheral VD

Regular use => decreased opioid use
Starting point for all pain management

ADRs - rare
CI - none
Warnings
-IV dosing based on weight, liver/kidney issues
-care needed when combining with other paracetamol containing products

Max dose - 4g daily in adults

Question 3

Ibuprofen

• MOA
• SE
• CI, warnings
• max dose

Answer 3

Analgesic and antiinflammatory - inhibit prostaglandin synth (act on COX12)

Suitable for inflammatory, bone, renal colic pain
Regular use => decreased opioid use

GI
-reflux, N+V, gastric ulcers/bleeds, diarrhoea
Renal
-affects kidney function => AKI,CKD, drug metabolism
Resp
-NSAID induced bronchospasm => worsen asthma
CV
-increased risk of thrombotic events in high risk patients

Question 4

Opioids

• MOA
• SE
• examples of ones used

Answer 4

Analgesia - opioid receptors in CNS => decreased pain perception, reaction and increased tolerance

Weak - used in addition to paracetamol+NSAIDs (dihydrocodiene)
Strong (morphine sulphate) - if weak opioids are insufficient

Regular review of opioids

Common ADRs

• sedation, dizzy
• N+V => antiemetics
• tolerance
• constipation => stimulant laxatives
• itch => antihistamines

ADRs related to high dose changes

• sedation => rep depression
• low HR, RR

Question 5

When and how to use opioids

Answer 5

Suitable for acute, EoL pain
-not helpful for long term pain

Long term opioid pain relief can be of benefit if dose is low, use is intermittent

Increased risk of harm at PO morphine 120mg/day+ with no increased benefit

Stop opioids if pain remains severe even if no alternatives available
-tapering, stopping high doses needs MDT collaboration

Start low and slowly titrate up

Question 6

How to choose a suitable NSAID

Answer 6

Chose lowest risk first - ibuprofen (400mg TDS)
Use 1 at a time at BNF doses
Short term use

PPI in

• 65+
• Hx of peptic ulcers/bleeding/performations
• PO CS/AC
• comorbidities
• prolonged use at max dose

Question 7

Factors affecting choice of opioid

Answer 7

Onset
-rapid onset/slow prolonged effect

Duration
-short/intermediate

Routes of administration

• swallowing?
• patient preference
• IV/SC/IM

Patient choice

• frequency of dosing
• tolerability

Question 8

Difference between

• tolerance
• dependence
• withdrawal
• pseudoaddiction
• addiction

Answer 8

Tolerance - same dose dose not provide same amount of analgesia
-difficult to differentiate from increased pain

Dependence - body cannot function without analgesia
-dose reduction/withdrawal => withdrawal effects

Withdrawal - symptoms that arise when drug is stopped suddenly/dose tapered too quickly/antagonist given

• SNS response
• increased pain, V+D

Addiction - impaired control, compulsive, continuous use despite harm and craving of a behaviour

Pseudoaddiction - behvaiours that may be mistaken as addiction but are an attempt to obtain better pain relief

• when pain is relieved => behaviours stop
• drug hoarding, attempts to obtain extra supplies, requests for early prescriptions, increased dose

Question 9

Benefits of multimodal analgesia

Answer 9

Additive and synergistic effects
-opioid sparing

P+O
N+O
N+P