pharmacology of analgesia Flashcards
what does paracetamol do?
anti pyretic
analgesic
NOT antiinflammatory
why does paracetamol not have any anti inflammatory effects?
paracetamol inhibits peroxidase activity
peroxides are produced by inflamed tissues, outcompete paracetamol for peroxidase enzyme
What are some weak opioids?
codeine
tramadol
What are some strong opioids?
morphine
fentanyl (heroin)
MOA opioids (4)
Depressant effect
Multiple sites inn pain pathway where activation of opioid receptor leads to decreased perception or increased tolerance to pain.
Anti-tusssive effect due to decreased activation of afferent nerves relaying cough stimulus from airways to brain
drug target for opioids
opioid receptor on nocireceptors
GABA
Side effects of opioids?
Vomiting
Nausea (increase activity in chemoreceptor trigger zone)
Constipation (reduced motility)
overdose causes respiratoory depression
what happens in opioid overdose?
respiratory depression via direct and indirect inhibition of respiratory control centre
MOA of co-amoxiclav
amoxicillin - binds to bacterial penicillin binding proteins
prevents transpeptidation for cell wall synthesis
clavulanate - beta lactamase inhibitor, bacterial enzyme which degrades penicillins (reduces resistance to antibiotics by inhibiting this)
drug target for co-amoxiclav?
amoxicillin - penicillin binding proteins
clavulanate - beta lactamase
side effects of co-amoxiclav?
well tolerated
nausea and diarrhoea possible
MOA of lactulose
non-absorbable disaccharide
causes water retention via osmosis as reaches the large intestine undigested
makes stool easier to pass
can be metabolised by colonic bacteria inducing a laxative effect
side effects of lactulose?
abdominal pain
diarrhoea
flatulence
nausea
how long does it take lactulose to be effective?
2 days to improve constipation
onset within 8-12 hours
how to know someone has overdosed on opioids
cardiorespiratory depression
unconscious
cyanosis secondary to resp depresh
pin prick pupils when unconscious
