Pain + Analgesics

Question 1

What are the main categories of pain?

Answer 1

Nociceptive (tissue damage, acute)

Neuropathic (neuronal damage, chronic)

Question 2

What is hyperalgesia

Answer 2

Hypersensitivity to pain

Question 3

What is allodynia?

Answer 3

Triggering of a pain response from stimuli which do not normally provoke pain

Question 4

What is nociceptive pain?

Answer 4

Caused by physical damage resulting in activation of free nerve endings

Question 5

What is neuropathic pain?

Answer 5

Results from neuronal damage and includes symptoms such as shooting/ burning pain and paraesthesias (e.g. tingling, numbness, pins and needles)

Question 6

Give examples of neuropathic pain

Answer 6

Phantom limb 
Trigeminal neuralgia 
Malignant pain 
Post-stroke (thalamic) pain 
Post-herpetic pain 
Complex regional pain syndrome (CRPS)

Question 7

Give examples of nociceptive pain

Answer 7

Lower back pain
Myofascial (muscle) pain
Arthritis
Visceral pain (e.g. cystitis, pancreatitis)

Question 8

What are the 5 types of headache?

Answer 8

Tension 
Sinus 
Migraine
Cluster
Medication overuse headache

Question 9

What type of headache is a clinical emergency?

Answer 9

‘Worst ever headache’

Subarachnoid haemorrhage

Question 10

What is the standard treatment for tension headaches?

Answer 10

NSAIDs

Determining triggers

Question 11

What is the standard treatment for sinus headaches?

Answer 11

Decongestant
Antihistamines
Steroids

Question 12

What is the standard treatment for migraine headaches?

Answer 12

3 step approach:
1. NSAIDs +/- antiemetics
2. Rectal NSAIDs +/- antiemetics
3, Anti-migraine drugs (triptans)

[Avoid opioids!]

Question 13

Why does chronic pain develop?

Answer 13

Badly managed acute pain 
Emotional sensitivity/ poor coping skills
Previous experience
Surgical complications 
Genetic predisposition

Question 14

What are the non-pharmacological options for pain management?

Answer 14

Exercise/ physiotherapy
Acupuncture
Transcutaneous Electrical Nerve Stimulation (TENS)

Question 15

What invasive procedures are used to manage pain?

Answer 15

Nerve blocks/ injections (e.g. steroids)
Ablation (removal of neurones from region of pain)
Implants (e.g. pumps, neuromodulators)

Question 16

What pharmacological options are available for managing nociceptive pain?

Answer 16

NSAIDs

Opioids

Question 17

What pharmacological options are available for managing neuropathic pain?

Answer 17

Tricyclic antidepressants (amitriptyline, nortriptyline)
Antiepileptics (gabapentin, pregabalin)
Can be used in combination with carbamezapine

Question 18

What is the WHO ladder for cancer pain control?

Answer 18

Pain free
Low level pain - treated by non-opioid analgesic
Mid level pain - treated by weak opioids
High level pain - treated by strong opioids

Question 19

What is the MoA for NSAIDs?

Answer 19

Blocks production of prostaglandins by inhibiting COX enzymes (1+2)

Question 20

Which COX enzyme is involved in the inflammatory response?

Answer 20

COX enzyme 2

Question 21

What NSAIDs are specific COX-2 inhibitors?

Answer 21

Celecoxib

Etoricoxib

Question 22

How do NSAIDs affect cells at a neuronal level?

Answer 22

Removal of prostaglandins

Question 23

What is salicylism?

Answer 23

Salicylate toxicity due to ingestion of NSAIDs

Question 24

How can NSAID intoxication be treated?

Answer 24

Fluid replacement
Haemodialysis
Activated charcoal
IV Lorazepam/ Diazepam (for seizures)

Question 25

What are the key symptoms of NSAID intoxication?

Answer 25

``` Tinnitus Pulmonary and cardiovascular symptoms CNS symptoms Renal failure Coma ```

Question 26

What are the 3 groups of opioids?

Answer 26

Agonists Partial agonists (or mixed agonists-anatgonists) Antagonists

Question 27

What drugs are opioid agonists?

Answer 27

``` Strong = morphine, diamorphine, tramadol Weak = codeine, dihydrocodeine ```

Question 28

What drugs are opioid partial agonists/ mixed agonist-antagonist?

Answer 28

Buprenorphine

Question 29

What drugs are opioid antagonists?

Answer 29

Naloxone | Naltrexone

Question 30

Where in the CNS do opioids act?

Answer 30

Mu, kappa, delta opioid receptors (OP1-4) | ORL1

Question 31

What are the key side effects of opioids?

Answer 31

Respiratory depression Conscious depression/ mood alterations Miosis

Question 32

What are the key indicators of opioid overdose?

Answer 32

Pupillary constriction Respiratory depression Coma (GCS <7)

Question 33

What treatment is used for opioid overdose?

Answer 33

Opioid antagonists (e.g. naloxone, naltrexone) Oxygen Glucose Thiamine

Question 34

What drugs can be used as migraine prophylaxis?

Answer 34

Beta-blockers | Amitriptyline (tricyclic antidepressant)

Question 35

What is the MoA of opioids?

Answer 35

Mimic endogenous opioids acting on opioid receptors to modulate pain at all CNS levels. Hyperpolarises neuron so it is less likely to fire when a stimulus comes through