Opioids

Question 1

What are opioids?

Answer 1

Endogenous or synthetic substance with morphine-like effects antagonized by naloxone.

Question 2

What is a opiate?

Answer 2

‘Opiate’ synthetic morphine-like drug with a non-peptide structure.

Question 3

What are types of opioid analgesics?

Answer 3

Agonists - Morphine, heroin, codeine.
Antagonists - Naloxone
Synthetic derivatives - Pethidine, methadone, fentanyl.

Question 4

What are the types of opioids?

Answer 4

Analgesia - morphine effective in most acute and chronic pain.

Euphoria - Strong sense of contentment and anxiety with pain.

Respiratory depression - sensitivity of respiratory centre to CO2 and mediated by u receptors.

Question 5

What are the effects of opioids?

Answer 5

Cough reflex - courtesy of codeine.
Nausea and vomiting
Pupil constriction
GI tract
Tolerance
Physical dependence
Pharmacokinetic properties

Question 6

What are the uses for the different opioid analgesics?

Answer 6

Diamorphine - Tissue injury, tumour growth.
Pethidine - Favoured for analgesia during labour.
Fentanyl - More rapid onset and shorter duration than morphine.
Codeine - Readily absorbed, only 20% potency of morphine.
Dihydrocodeine - 10% of population who are resistant to codeine.
Tramadol - opioid agonist and weak NA reuptake inhibitor.

Question 7

What are the treatments for neuropathic pain?

Answer 7

Opioids
Antidepressants
Blockade of ion channel

Question 8

What are the treatments for mild and severe pain?

Answer 8

Mild pain - NSAIDs or paracetamol or by weak opioids supplementation (codeine, co-codamol, tramadol).

Severe pain - strong opioids (morphine, fentanyl, oxycodone).