Opioids and Pain Flashcards Preview

Pharmacology > Opioids and Pain > Flashcards

Flashcards in Opioids and Pain Deck (19):
1

Nociception

The physiological processes in response to a noxious stimulus
Very immediate
Activates particular sensory nerve

2

Allodynia

Pain in response to a normally innocuous stimulus

3

Hyperalgesia

Enhanced pain to a normally painful stimulus

4

Nociceptive Pain

Direct activation of nociceptors by noxious stimuli
Ex: touching something hot

5

Inflammatory Pain

Activation by inflammatory mediators
Ex: rheumatoid arthritis

6

Neuropathic Pain

Pain arising from nerve damage
Ex: Postherpetic neuralgia
Patient looks normal, but damage to nervous system causes extreme pain

7

Opiate

Drug derived from opium

8

Opioid

Agents with opiate-like actions
- synthetic drugs
- proteins that mimic opiate actions
(endorphins)

9

Narcotic

2 Definitions
1. Sleep inducing (Pharmacological)
2. Drugs producing dependence (Legal)

10

During acute inflammation...

Upregulation of opioid receptors
Opioid analgesia very effective

11

During chronic inflammation...

Downregulation of opioid receptors
Opioid analgesia less effective

12

Negative Side Effects of Opioids

Severe constipation, somnolescence, cardiorespiratory depression
Tolerance
Dependence (Addiction)

13

Physical Dependence

Drug withdrawal produces physical abstinence syndrome:
Mild: lacrimation, sweating, yawning
Severe: anorexia, cramps, nausea, vomiting, restlessness, irritability, tremor, HR/BP changes, chills, spasms, PAIN

14

Psychological Dependence

Compulsive drug seeking behaviour
Occurs with drugs with mood enhancing properties
Activates dopaminergic circuits (endogenous reward systems)

15

Treatment of Dependence

Cessation of drug intake
Naltrexone (μ-antagonist)
Methadone (μ-agonist – good oral availability (no more injections), selective, long-lasting/slow withdrawal

16

Peripherally restricted opioids

Can target pain at the source
Reduce sensitization of nociceptors
Do not pass the blood brain barrier therefore less likely to cause addiction issues, centrally-mediated side-effects (e.g. respiratory depression)

17

How to improve opioid receptor levels

Inhibit β-arrestin activity = reduced receptor internalization
Inhibit receptor degradation (protease inhibitors)
Promote receptor recycling

18

4 Opioid receptor subtypes and their function

Mu, kappa delta (inhibit neuronal depolarization)
NOP (neuronal depolarization

19

2 Ways to reduce pain transmission

1. On presynaptic nerve terminal: opioid binds, reduces release of excitatory NTs and reduce Ca input which feeds back into inhibition of release
2. On postsynaptic nerve terminal: increase K permeability (hyperpolarization)