pain management

Question 1

Somatic pain

Answer 1

Tender and localised to site of injury

Constant and sometimes throbbing or aching

Question 2

Visceral pain

Answer 2

Mediated by stretch receptors

Poorly localised, deep, dull and cramping

Question 3

Neuropathic pain

Answer 3

Prolonged, severe, burning, lancinating or squeezing

Associated with focal neurological deficits

Question 4

Referred pain

Answer 4

Located away from point of origin

Question 5

Ischemic pain

Answer 5

From loss of blood flow to tissue

Question 6

Socrates

Answer 6

Site 
Onset 
Character 
Radiation 
Associations 
Time course 
Exacerbating/relieving factors 
Severity

Question 7

Non-opioids

Answer 7

Paracetamol

NSAIDS (ibuprofen)

Question 8

Weak opioids

Answer 8

Codeine
Tramadol
Tapentadol
DMP

Question 9

Strong opioids

Answer 9

Morphine 
Fentanyl 
Oxycodone 
Hydromorphone 
Methadone 
Nerve block/spinal analgesia

Question 10

Neuropathic pain adjuvants

Answer 10

Gabapentin 
Pregabalin 
Antidepressants (TCAs)
Antiepileptics 
Topical lidocaine 
Corticosteroids

Question 11

Bone pain adjuvants

Answer 11

Corticosteroids
NSAIDs
Biphosphates

Question 12

Muscle pain/spasms adjuvant

Answer 12

Muscle relaxants

Benzodiazepines

Question 13

Intestinal colic adjuvant

Answer 13

Hyoscine (buscopan)

Question 14

Codeine

Answer 14

For moderate pain
Reduced efficacy with 2D6 inhibitors
Codeine : Morphine = 10:1

Question 15

Tramadol

Answer 15

Indicated for moderate pain
Compelling indication for somatic and neuropathic pain 
Less CV and respiratory effects 
Reduced efficacy with CYP2D6 inhibitors 
Max 400mg/day 
Lowers seizure threshold in high doses
Tramadol : Morphine = 5:1

Question 16

Morphine

Answer 16

Oral: parenteral = 3:1
Avoid with CNS depressants
Risk of hypotension with antipsychotics
Avoid in renal, hepatic impairment
Starting dose: 
- weak opioid previously: 10mg Q4h 
- frail/elderly: 5mg Q4h

Question 17

Fentanyl

Answer 17

100mcg fentanyl = 10mg morphine 
Suitable in renal and hepatic impairment 
Indicated for patients with 
- undesirable side effects from morphine,
- renal failure
- dysphagia (with patch)
- tablet phobia/poor compliance
3A4 inhibitors reduces elimination
Shorter duration of action

Question 18

Methadone

Answer 18

Compellingly indicated for patients with opioid tolerance, with neuropathic components in somatic pain
CYP3A4 inhibitors increase efficacy, inducers decrease efficacy
Dose adjustment in renal impairment, CI in hepatic impairment

Question 19

Oxycodone

Answer 19

Alternative for morphine intolerant
Q6h instead of Q4h for morphine
CYP3A4 and 2D6 inhibitors decrease effectiveness
Oxycodone : Morphine : 0.5:1

Question 20

Pethidine

Answer 20

DA in renal and hepatic impairment 
Short duration of action
Toxic metabolites 
Increases risk of seizure
More emetogenic