Analgesics in MOS 3 Flashcards
What is the NNT for 60 mg of codeine?
16.7
What is the NNT of 60mg codeine in combination with 1g of paracetamol?
2.2 (1.8-2.9)
hence it has a higher efficacy
based on data from 197 patients
Opioids are effective for what kinds of pain following oral surgery?
moderate to severe pain
What are some side effects of opioids?
- nausea
- vomiting
- constipation
The WHO pain ladder was originally applied to the management of ____ pain. However, it is now applied to the management of all types of pain
cancer
Give examples of mild opioid drugs
codeine phosphate dihydrocodeine
tramadol
Give an example of a stronger opioid drug
morphine
What is an opioid?
this is a compound that has pharamacologucal activity at an opioid receptor. It may be endogenous or administered, naturally occuring or synthetic
What is an opiate?
this term is strictly reserved to describe alkaloids that are derived naturally from the opiate poppy (papaver somniferum)
What is the UK definition of a narcotic?
an addictive drug affecting mood or behaviour
What is the USA definition of a narcotic?
narcotic refers to opioids for medicinal use as well as illegally used opium derivatives
What is opium?
an extract of the juice of the poppy which has been used for social and medicinal purposes for thousands of years as an agent to produce analgesia, euphoria and sleep
What is the most abundant opiate found in opium?
morphine
Give examples of synthetic compounds that have been produced by chemical modification of morphine
- codeine
- diamorphine
- pethidine
How do opioids differ from one another?
- relative efficacy
- pharmakokinetics (body does to the drug)
- other actions
How can the effects of opioids be reversed ?
opioid antagonist such as naloxone
How have opioids been traditionally classified?
- weak
- intermediate
- strong
What adverse side effect does high dose codeine cause?
respiratory depression
What are the 3 principal classes of opioid receptors?
- u- mu
- kappa
- delta
Opioids produce majority of their therapeutic and adverse effects by acting as agonists at ____ receptors
- u- mu receptors
Endogenous opioids do not cause any side effects. True or false
true
Opioids also exhibit a ceiling effect similar to non-opioid analgesics. True or false
False
the analgesic response to the opioids acting on the u-receptors continues to increase with increasing dose
What is the recommended analgesic regime for mild pain following a forceps extraction?
paracetamol 1g every 6 hours regularly (maximum fo 4g/24 hours)
What is the recommended analgesic regime for moderate pain following surgical removal of a tooth?
ibuprofen 400mg every 6 hours
(maximum 2.4g/24 h) and paracetamol 1g every 6 hours as necessary
What is the recommended analgesic regime for severe pain following surgical removal of a tooth involving bone removal ?
ibuprofen 400mg every 6 hours regularly (maximum 2.4g/24hours) and paracetamol 1g/codeine 60 mg combination every 6hours regularly
Opioids are often localised in high concentrations in highly perfused tissues. Give examples of such tissues
- lungs
- liver
- kidneys
- spleen
What is the most common route of administration of opioid analgesics ?
orally
________ preparations of opioids are more rapdily absorbed than solid preparations
liquid
Why might the oral dose of opioids required to provide sufficient analgesic relief be higher than the dose required if it were administered parenterally?
this is due to significant first pass metabolism by glucoronidation in the liver
IM injections of opioids can be administered. Give examples of muscles most often used
- deltoids
- vastus lateralis muscles
Why are IM opioid injections not ideal?
- painful
- not acceptable to some patients
- variable absorption
*
Why must IV administration of opioids be done slowly?
to minimise adverse effects
What are the key requirements for IV administration of opioids?
- skilled nursing
- pharmacy support
- infusion pump for continuous or patient controlled administration
What opioid is available via a transdermal drug delivery system ?
fentanyl
Why are transdermal opioids contraindicated for use in acute post-operative pain?
this is because they are slow release
high incidene of side effects
What drug is the gold standard for acute pain management?
morphine