Exam 1 Flashcards
what about the structure of LAs increases their lipophilicity?
longer hydrocarbon chain and interconnecting chain
how do ester and amide LA metabolism differ?
esters - metabolized by plasma and liver pseudocholinesterases
amides - metabolized by liver P450s
how does LA change on either side of the cell membrane?
outside - uncharged
inside - becomes charged (this is what blocks the channel)
which drugs are used for topical anesthesia
benzocaine and cocaine
procaine and lidocaine can both be used for which 3 forms of LA?
infiltration (injection), epidural, spinal
why does LA getting to the brain cause convulsions?
d/t blockade of the GABA-A receptors (causes decr inhibition)
how is cocaine the exception when it comes to LAs having adverse cardio effects?
causes tachycardia, vasoconstriction, HTN
how does Epi affect the action of LAs?
it incr the LA action by 50%
how does diazepam aid in the tox caused by LAs?
treats convulsions d/t systemic absorption by activating the GABA-A receptors in the CNS
how is clonidine used as an adjunct in LA admin?
decr substance P and glutamate release (decr pain transmission)
which routes of LA admin is clonidine used in?
epidural and spinal
what are the protective components of the stomach?
mucous, bicarbonate, PGE
why do you need to be careful with cimetidine?
it is metabolized by CYPs so can interact with warfarin and phenytoin
which patients need a dose adjustment for H2 blockers?
renal insufficiency
how long does one dose of omeprazole work for?
t1/2 = 1.5hrs, however decr acid secretion for 2-3 days
rare side effects of omeprazole
nausea, diarrhea, dizziness
how do PPIs affect the bones with longterm use?
decr acidity decr the amount of Ca absorbed so bones more fragile
what is the first choice treatment in Zollinger-Ellison syndrome?
omeprazole
what indication is omeprazole less than ideal for?
occasional heartburn
which upper GI drugs can you develop a tolerance to?
H2 blockers
when can antacids be taken?
after a meal when there is acid present
what AE does Mg(OH)2 have if given alone?
diarrhea
what AE does Al(OH)3 or CaCO3 have if either are given alone?
constipation
how can antacids affect the urine?
they can increase the pH and alter the elimination of acidic and basic drugs
which drugs do Al(OH)3 and CaCO3 alter the absorption of?
tetracycline, INH, ketoconazole
which drug must be admin 2 hours after tetracycline, phenytoin, and digoxin and why?
sucralfate b/c it can absorb other drugs
when must sucralfate be admin?
before a meal
what strange AE does bismuth cause?
blackened tongue and stool
why can’t bismuth be used in children?
salicylate acid causes Reye’s syndrome
what is bismuth esp good for and why?
H. pylori infection d/t antimicrobial feature
what is misoprostol CI in?
pregnancy (d/t induction of contractions)
which drugs is B12 malabsorption associated with? why?
PPIs
d/t the fact that B12 absorption needs an acidic environment
where is the majority of 5-HT produced?
guts
how does metoclopramide affect the LES and pyloric sphincters?
incr LES tone to prevent backup
relaxes pyloric sphincter tone to incr gastric emptying
how do the MOAs for metoclopramide and ondansetron differ?
metoclopramide - D2 & 5-HT3 antagonist; 5-HT4 agonist
ondansetron - 5-HT3 receptor antagonist
how can ondansetron effectiveness be incr?
adding dexamethasone or aprepitant
metoclopramide AEs
parkinsonism like sx, tardive dyskinesia
ondansetron AEs
constipation and headache/GI sx
why can’t linaclotide be used in children
reports of mortality d/t dehydration in mice
how do linaclotide and lubiprostone MOAs differ?
Linaclotide - activates CFTR via cGMP
Lubiprostone - directly activates ClC2 Cl channel
what type of solution is Mg(OH)2 as an osmotic laxative and how does this affect its MOA?
admin as hypertonic solution which incr osmotic pressure and causes accumulation of fluids in GI tract
what are the indications for saline laxative (MgOH2)?
colonoscopy prep
IBS-C
how do steroids help IBD?
reduce ulceration and cause initial remission