opioid pharmacology Flashcards
what are the naturally occurring opioids?
morphine
codeine (weak)
What are the drugs that were made from simple chemical modifications of the naturally occurring opioids?
diamorphine
oxycodone
dihydrocodeine
what are the synthetics opioids?
pethidine
fentanyl
alfentanil
remifentanil
What is a synthetic partial agonist of the opioids?
buprenorhine
Which drug is an antagonist of the opioids?
naloxone
What are the routes of administration of the opioids?
subcut IM IV IV (PCA - pt controlled analgesia) epidural/CSF transdermal patches for fentanyl
What percentage of oral (enteral) morphine is metabolised in first pass metabolism and what does this mean if giving the drug IV/subcut/IM ie via parenteral routes?
50% - half the dose if parenteral route used
How long dose a single dose of morphine last for?
3-4 hours
What are MST CONTINUS tablets and how often are they given?
slow release preparations of morphine given 12 hourly
What is diamorphine?
morphine that has been chemically transformed into diacetylmorphine
How does diamorphine compare to morphine?
more potent and faster acting, as crosses the BBB faster (called heroin) - so more addictive
What class are opioids?
class A
What drug is given to drug addicts?
bupromorphine - partial opioid agonist
Why is it important to titrate the amount of naloxone?
Because if all the morphine is blocked suddenly, the pt may wake up in pain, so give small increases in dose at a time
How fast does IV morphine take to work?
1 minute
How long does it take for subcut morphine to peak?
1 hour
What is the difference between potency and efficacy?
potency - how much do you need to give to get the effect
efficacy - how much of it that you give actually does the effect that you want