Opioids Flashcards
action of pure agonists
all receptors are turned on
mixed agonist-antagonist action
some receptors are turned on while others turned off
- get pain relief with out the other side effects
pure antagonists
reverse the side effects of the agonists, and help with constipation by blocking receptors in gut but cannot cross BBB so you still get pain relied
side effects of agonists
respiratory depression
constipation
euphoria
decrease cough reflex
sedation
mitosis (no pupil dilation)
side effects of agonists and antagonists
analgesic ceiling: maximum level of pain relief (increase dose = no more pain relief)
hallucinations
dysphoria= opposite of euphoria
when switching to this form from a pure agonist it is important to understand there will be risks of withdrawal because receptors differ with drug class
what is not tolerance built to
miosis and constipation
cross tolerance
when switching from one agonist to another there is a chart that will show you the converted does, when completing this it is important that we decrease that does of the new drug to 25-50% in case toe cross over of tolerance is not complete
EX: 25 mg morphine= 50 mg codine and we reduce that to 25-50% which equals 25-37.5mg of codine
dependence vs addiction
dependence is the body gets use to the drug
addiction is the mental crave of the drug not for the intended use
how long chronically when taking an opioid will you develop withdrawl
2 weeks
examples of withdrawal
sweating, irritablity, tremor, nausea, vomitting, spasms
how to minimize the withdrawal symptoms
tapering the drug over 3-7 days
what effects how long you taper a drug
dose and the how long been on the drug
how do younger and older age individuals differ in response to agonists
need lower dosing
renal impact and morphine
morphine contains active byproducts which are removed via the kidney and when patients have bad kidneys the byproducts build up and amplify the effects of morphine and exacerbate pain
morphine vs other agonists
morphine is not absorbed well orally
tramadol vs agosnists
blocks norepinephrine and serotonin, good for nerve pain
weak form and morphine so be aware of same side effects
codine pharacogenics
codine is turned into morphine via CYP2D6 which normally there is 2 copies and converts 15% of codeine. some individuals do not have this enzyme so they get no pain relief. others who are UM have 13 copies and they have more morphine effects which can lead to harm if unknown
who are at risk for codine
children <12 no, <18 no if rest issues
post part women because if UM then transferring the morphine to infant via breast milk
agonists
morphine, codine, oxycodone, hydrocodone, hydromorphone, tramadol
agonist and antagonist
buprenorphine
resp depression can have a tolerance but what will exacerbate the tolerance and make it disapate
other CNS depressants (alc and Xanax)
