Pharmacology of Pain

Question 1

Opioids

Answer 1

Diversity of opioid peptides- Enkephalins, dynorphins, beta-endorphin
Peptides derived from large molecular weight precursors
–> enkephalins from proenkephalin
Peptides are targets for peptidases

Question 2

Endogenous opioid systems

Answer 2

Proopiomelanocortin-derived
Proenkephalin-derived
Prodynorphin-derived

Question 3

Opioid receptors

Answer 3

Mu- 1,2,3
Delta- 1,2
Kappa- 1,2,3
Nociceptin/orphanin
Opioid receptors are widespread

Question 4

Morphine MOA

Answer 4

Attaches to receptor in cell
Activation of potassium conductance and decreased calcium conductance
Ca2+ entry blocked
–> decreased excitability + decreased release of neurotransmitters

Question 5

Effects mediated by main opioid receptors

Answer 5

Analgesia
Resp. depression
Pupillary constriction
Reduced GI motility
Sedation
Euphoria
Dysphoria
Dependence

Question 6

Types of opioid

Answer 6

Codeine
Methadone
Morphine
Oxycodone
Tramadol

Question 7

Effects of opioids- CNS

Answer 7

Analgesia
Resp. depression
Drowsiness
Euphoria
Miosis
Nausea + vomiting

Question 8

Effects of opioids- CV system

Answer 8

Hypotension

Question 9

Effects of opioids- GI

Answer 9

Delayed gastric emptying

Decreased biliary and pancreatic secretions

Question 10

Other Effects of opioids

Answer 10

Urinary urgency

Itching

Question 11

Morphine

Answer 11

M6G active metabolite

Question 12

Heroin

Answer 12

High solubility compared to morphine

Question 13

Dextromoramide

Answer 13

Active sublingually

Question 14

Meptazinol

Answer 14

Less resp. depression

Mu 1 receptor agonist

Question 15

Warnings of opioid use

Answer 15

Resp. depression
Toxicity
Accumulation of methadone
Accumulation of M6G if renal function impaired

Question 16

Opioid tolerance

Answer 16

Depends on genetic background + ethnicity

Can switch opioids when patients become tolerant to particular opioid drug

Question 17

Analgesic ladder

Answer 17

1= non-opioids + adjuvant drugs
2= moderate efficacy opioids, non-opioids and adjuvant drugs
3= high-efficacy opioids, non-opioids and adjuvant drugs

Question 18

Paracetamol

Answer 18

Reduced active oxidised form of COX2
Modulates endogenous cannabinoid system
Analgesic
Antipyretic
Little anti-inflammatory

Question 19

Aspirin

Answer 19

COX1 and COX2 inhibitor
Analgesic
Antipyretic
Anti-inflammatory

Question 20

Ibuprofen, diclofenac, ketoprofen

Answer 20

COX1 and COX2 inhibition

Analgesic and anti-inflammatory

Question 21

Rofecoxib

Answer 21

Selective COX2 inhibitor

Question 22

NSAID indications

Answer 22

RA
OA
Dysmenorrhea
Gout
Muscle spasm

Question 23

NSAID SE

Answer 23

Nausea

GI bleeding

Question 24

NSAID Combinations

Answer 24

Codeine/paracetamol

Dihydrocodeine/paracetamol

Question 25

Anticonvulsants

Answer 25

Cabamazepine, sodium valproate, pregabalin Neuropathic pain Trigeminal neuralgia

Question 26

Carbamazepine MOA

Answer 26

Acts on Na channels

Question 27

Na Valproate MOA

Answer 27

Acts on Na channels

Question 28

Pregabalin

Answer 28

Acts on alpha 2 delta subunit on Ca channels

Question 29

Tricyclic antidepressants

Answer 29

``` Inhibit reuptake of amines Block Na and Ca channels Amitriptyline Neuropathic pain Cancer pain ```

Question 30

Migraine pain

Answer 30

Triptans | Ergotamine derivatives

Question 31

Antidepressants

Answer 31

TCA | SSRI

Question 32

Anticonvulsants

Answer 32

Na channels

Question 33

Calcium channel ligands

Answer 33

Gabapentin Pregabalin Verapamil

Question 34

Vanilloid receptors

Answer 34

TRPV family ligands | Capsaicin

Question 35

NMDA glutamate receptors

Answer 35

Ketamine | Dextromethorphan

Question 36

GABA receptor agonists

Answer 36

Baclofen

Question 37

Local anaesthetics

Answer 37

Lignocaine, bupivacaine, prilocaine Block Na channels Surface, infiltration, epidural Risk of systemic toxicity - hypotension, resp. depression, bradycardia

Question 38

Inhalational general anaesthetics

Answer 38

``` Halothane NO Xenon Isoflurane Enflurane ```

Question 39

IV general anaesthetics

Answer 39

Propofol Thiopental Ketamine

Question 40

Trigeminal neuralgia

Answer 40

``` Most common facial pain syndrome Tic douloureux Sudden, paroxysmal attacks of pain Commonly unilateral Cheekbone, nose, upper lip + teeth ```

Question 41

Trigeminal neuralgia cause

Answer 41

Compression Distortion Stretching of V nerve root fibres by branch of AICA or PICA

Question 42

Trigeminal neuralgia treatment

Answer 42

Carbamazepine Baclofen Valproate Clonazepam