Analgesic Drugs

Question 1

Peripheral sensitisation

Answer 1

Increases the action of the nociceptive stimuli in order to reduce subsequent injury to the area

Question 2

Descending inhibition of nociception

Answer 2

Decreases the pain felt by acting on the spinal cord.

Question 3

Analgesic drugs

Answer 3

Opiate drugs
NSAIDs (non-steroidal anti-inflammatory drugs)
Other analgesics

Question 4

WHO pain ladder

Answer 4

Mid pain - NSAIDs (aspirin, ibuprofen)
Moderate pain - low potency opioids (codeine, buprenorphine)
Severe pain - high potency opioids (morphine, fentanyl)

Question 5

Effects of NSAIDs

Answer 5

• Anti-inflammatory (paracetamol is not, we don’t know why)
• Anti-pyretic (decrease fever)
• Analgesic
  All effects related to decreased prostaglandin synthesis
  Effects are additive, but toxicity is not

Question 6

Examples of NSAIDs

Answer 6

Aspirin, ibuprofen, diclofenac, paracetamol

Question 7

Decreased synthesis of prostaglandins does what?

Answer 7

It decreases the action of bradykinins, VGNa And Wr-1.

Question 8

NSAIDs and COX

Answer 8

NSAIDs inhibit both COX-1 and COX-2
COX converts Arachidonic acid to protaglandin H2 in the production of protaglandin E2

Question 9

Disadvantage of NSAIDs

Answer 9

PGs are involved in a lot of processes, so decreasing them leads to:
* severe gastric irritation
* kidney disorders
* paracetamol overdose

Question 10

COX-2

Answer 10

Only COX-2 causes the desired effect.
* COX-1 is widespread throughout the body and causes side effects
* COX-2 is just involved in the inflammatory response

Question 11

COX-2 inhibitors

Answer 11

Rofecoxib (vioxx) was a very effective treatment for rheumatoid arthritis, but had a small chance of cardiac side effects.
Celecoxib (celebrex) does the same thing but hasn’t been pulled because side effects are known.
Other NSAIDs also have this cardiac risk, but the chances are very low.

Question 12

Neuropathic pain

Answer 12

Pain unrelated to peripheral nociception
Sometimes called pathological pain
Generally don’t respond to opioids or NSAIDs

Question 13

Causes of neuropathic pain

Answer 13

Generally by peripheral nerve damage
Peripheral nerve terminal damage or infection
Spinal damage
Thalamic stroke

Question 14

Tricyclic antidepressants

Answer 14

e.g. imipramine
Work for shingles-caused neuropathic pain

Question 15

Antiepileptic drugs

Answer 15

e.g. gabapentin
Neuropathic pain

Question 16

Cannabinoid receptor agonists

Answer 16

Central and peripheral effects
Neuropathic pain (esp. multiple sclerosis)

Question 17

Glutamate receptor blockers

Answer 17

MK801
Block afferent transmission
Severe side effects

Question 18

Neurokinin receptor blockers

Answer 18

Block central sensitization
Has to be taken before pain such as before surgery

Question 19

Nociceptor blockers

Answer 19

TRPV1, P2X3, sodium channel
Block detection of noxious signals