(pharm) pharmacology of pain Flashcards
which drugs are commonly prescribed for pain?
paracetamol
opioids (codeine, tramadol, morphine, fentanyl)
co-amoxiclav
lactulose
what is the primary mechanism of action of paracetamol?
1) activation of descending serotonergic pathways possibly via 5HT3 receptor activation
2) inhibits reuptake of endogenous endocannabinoids, which would increase activation of cannabinoid receptors.
3) mild inhibition of cyclooxygenase
what is the drug target for paracetamol?
1) 5HT3 receptors
2) cannabinoid reuptake proteins
3) cyclooxygenase
what are the main side effects of paracetamol?
relatively safe drug w few common side effects
(nausea + vomiting early features of poisoning)
what can paracetamol overdose cause?
liver damage and less frequently renal damage
which hepatological complication can occur due to excess paracetamolintake?
hepatic necrosis
how does hepatic necrosis present in patient who take paracetamol?
onset of right subcostal pain after 24 hours
what type drug is paracetamol classed as?
analgesic & anti-pyretic
is paracetamol an anti-inflammatory drug?
no!
paracetamol does not have anti-inflammatory properties
what are the groups of opioids available?
mild and strong opioids
name weak opioids
codeine, tramadol
name strong opioids
morphine, fentanyl, heroin
what is the mechanism of action of opioids?
1) activation of the opioid receptor at multiple sites in pain pathway = decreased perception or increased tolerance to pain
2) anti-tussive effect due to decreased activation of afferent nerves relaying cough stimulus from airways to brain
what is the drug target for opioids?
opioid receptor
what are the mild side effects of opioid usage?
nausea + vomiting (increased activity in the chemoreceptor trigger zone)
constipation (opioid receptors in the GIT can reduce gut motility)
why can opioid use lead to nausea & vomiting?
increased activity in the chemoreceptor trigger zone of the medulla oblongate
why can opioid use lead to constipation?
increased opioid receptor activation in the GI tract causes reduced gut motility
why is opioid overdose dangerous?
causes respiratory depression (direct & indirect inhibition of respiratory control centre)
what is co-codamol?
paracetamol + codeine
what is co-dydramol?
paracetamol + dyhydrocodeine
which two drugs make up co-amoxiclav?
amoxicillin
clavulanate
what is the mechanism of action of co-amoxiclav?
amoxicillin = binds to bacterial penicillin binding proteins (PBPs) to prevent transpeptidation, inhibiting the cross-linking process required for bacterial cell wall synthesis
clavulanate = beta lactamase inhibitor
what are the drug targets for co-amoxiclav?
amoxicillin targets the penicillin binding proteins (PBPs)
clavulanate targets beta lactamase
what is the function of penicillin-binding proteins?
membrane-associated proteins involved in the biosynthesis of peptidoglycan (PG), the main component of bacterial cell walls