Weak Opioids : Codeine

Question 1

What is codeine used for?

Answer 1

• mild to moderate pain e.g. post operative.
  (2nd line to paracetamol)
  -rung to on the WHO pain ladder

Question 2

What is the mechanism of action of codeine?

Answer 2

• codeine is metabolised in the liver (by cytochrome P450 2D6) to produce small amounts of morphine.
• morphine is a stronger agonist of opioid u (mu) receptors.

Question 3

what is the difference between tramadol and codeine?

Answer 3

tramadol is able to affect serotonergic and adrenergic pathways as well as u-opioid receptors. It is a synthetic analogue of codeine.

Question 4

what are the side effects of weak opiods like codeine?

Answer 4

• constipation
• dizziness
• drowsiness
• neuro / respiratory depression

Question 5

What is the route of codeine?

Answer 5

DO NOT GIVE CODEINE IV!!! histamine release leads to reaction similar to anaphylaxis.

Question 6

What are the contraindications of codeine?

Answer 6

• significant respiratory disease
• weak opioids rely of liver and kidneys for elimination. so reduce doses in kidney or liver impairment and elderly.
• Tramadol lowers seizure threashold so avoid in epilepsy.

Question 7

What are the interactions of weak opioids such as codeine?

Answer 7

1) other sedating drugs e.g. antipsychotics, benzodiazepines, tricyclic antidepressants.
2) dont use tramadol with drugs that lower seizure threshold e.g. SSRIs, Tricyclic antidepressants.