Pharmacology Flashcards
what is the receptor on pre synaptic parasympathetic cells that decreases action of ACh?
dopamine receptors
what is the receptor on pre synaptic parasympathetic cells that increases action of ACh?
motilin receptors
what is the MOA of metoclopramide?
inhibits the dopamine receptor on parasympathetic nerves to increas ACh release
what is metoclopramide used for?
gastroperesis
since metoclopramide is a dopamine inhibitor…where are a lot of toxicities found with it?
CNS
name the two common CNS toxicities with metoclopramide ?
acute dystonia and tardive dyskinesia
what is the CNS pathway that metoclopramide inhibits that leads to acute dystonia and tardive dyskinesia?
nigrostriatal pathway
what hormone can metoclopramide cause to be at elevated levels? why?
prolactin…due to anti dopamine effects and dopamine usually inhibits prolactin release
name the antibiotic that can treat gastroparesis
erythromycin
what is the MoA od erythromycin for gastroporesis?
activates the motilin receptor on parasymp nerves
what is an issue with erythromycin that renders it less effective long term?
tachyphylaxis…or desensitization to the drug
what is the name of the direct acting parasymp agonist to treat gastroparesis?
Bethanechol
what is the MoA of bethanechol?
directly binds M3 receptors
what is the name of the indirect para agonist for gastroparesis?
Neostigmine
what is the MoA of neostigmine?
inhibits AChEsterase so increases ACh in synaptic junction
how is neostigmine administered? what must you have on hand to give? why/
IV
Antidote of atropine
Because it has all toxicities associated with ramping up the parasympathetic system
what is the drug that serves as a barrier for acid in ulcerative diseases?
sucralfate
what is the MoA of sucralfate?
polymerizes at low pH and has negative charge so can bind to positive charge of exposed cells in gut
how do antacids work?
they serve as buffers for acid in the GI tract
name the three common bases in antacids
bicarbonate
carbonate
hydroxate
bicarbonate can be absorbes so if you take a lot of it as an antacid what can this lead to?
metabolic alkalosis
why do you administer Al(OH) and Mg(OH) together
because Al causes constipation and Mg causes diarrhea so they cancel each other out
what molecule can get low when taking antacids? why is this?
hypophosphatemia because the antacids can bind the phosphate and make it insoluble and therefore cannot absorb it
what does histamine cause in the stomach? what molecule stimulate histamine release and what cell releases?
causes acid release
gastrin causes enterochromaffin cells to release histamine
what histamine receptors do histamine blockers for stomach acid target? is this one different from allergy histamine receptor?
H2…yes this is different than the H1 in the nasal area
name the four common anti histamine drugs for stomach acid
cimetidine
ranitidine
famotidine
nizatidine
what is the problem with cimetidine?
inhibits a bunch of CYPs in the liver
what drugs does cimetidine interact with through its CYP inhibition?
warfarin
clopidogrel
oral contraceptives
theophylline
what cells do PPIs target? what molecule on the cell?
parietal cells K+/H+ pump
do PPIs work by binding the pump in the cell or in the lumen?
luminal side of the pump
name the three toxicities of PPIs
vitamin B12 malabsorption
hypomagnesia
c diff
why do PPIs lead to vitamin B12 malabsorption?
because Vitamin B12 is bound to protein when ingested and the stomach acid promotes the unbinding and without the acid the B12 does not get freed and absorbed
what type of kidney issue can PPIs cause?
AIN
what is the ending of the PPIs?
prazoles
how do PPIs end up in the luminal area surrounding the parietal cells?
pH trapping…get + charge once in lumen and cannot leave
what is the role of prostaglandin 2 (PGE2) in stomach acid production?
it inhibits the production of stomach acid
name the drug that is a mimic of PGE2 that can help with stomach acid problems?
misprostol
what stomach acid drug should not be given during pregnancy?
misoprostol
what are the two main neurotransmitters that regulate the vomitting center?
serotonin and dopamine
name the serotonin antagonist that works as an anti emetic?
ondansetron
what is the toxicity of ondansetron to worry about?
prolonged QT interval
name the two dopamine antagonists that are anti emetics?
prochlorperazine
promethazine
why do prochloroperazine and promethazine not work as well for gastroparesis like metoclopramide does?
because they work more in the CNS and metoclopramide works mainly in stomach
name the three common toxicities of prochloroperazine and promethazine
prolonged QT interval
acute dystonia
tardive dyskinesia
