Flashcards in Gastroentergology Part 1 Deck (46)
lower esophageal sphincter
what in saliva helps neutralize acid in gastric reflux?
what drugs could inhibit (or antagonize) the tonic contraction of the LES (which is a SM)?
mechanism of antacids? onset? duration of action?
buffer acid on the luminal side
onset is <5 mins, duration of action is 20-30 mins
indicated ages for antacid therapy?
> or equal to 12 yo
when are antacids indicated? where do they act? caution with using antacid like tums?
indicated when having acid reflux
actions are limited to only while in stomach
CAUTION: should NOT be used when using medication that can cause chelation
ADRs of calcium carbonate?
may cause constipation/flatulence & approximately 10% of Ca2+ is absorbed into the blood
ADRs of magnesium hydroxide?
may cause diarrhea and about 20% of Mg2+ is absorbed into the blood
ADRs of sodium bicarbonate?
form Na+ Cl-, may not be great for persons on sodium restricted diets
ADRs of bismuth subsalicylate?
can cause dark stools (patient panic), tongue discoloration, hearing loss
ADRs from aluminum hydroxide?
some is absorbed and can accumulate causing altered mental status, esp in chronic KD dz, generally avoided
which antacid can cause constipation?
which antacid can cause diarrhea?
mechanism of histamine2-receptor antagonists? onset? duration?
selective, competitive blockade on basolateral side of receptors on parietal cells
onset: 30-45 mins
duration: 4-10 hrs
4 histamine2-receptor antagonists?
famotidine, ranitidine, cimetidine, nizatidine
what is tachyphylaxis?
taking H2RAs every day for more than a couple days/weeks can lead to tolerance and reduced effectiveness
ADRs of H2RAs?
anti-androgenic (reversible dynecomastia, rarely impotence), arrhythmias, h/a, dizziness, GI
major interactions with H2RAs?
st. John's wort, caffeine, cimetidine
mechanism of proton pump inhibitors? onset? duration?
selective, irreversible H/K/ATPase inhibition on luminal side of parietal cells
onset: 2-3 hrs
duration: 24 hrs
suffix of proton pump inhibitors?
ADRs of PPIs? metabolism?
Mg2+ depletion, osteoporosis, clostridium difficile infxns, community-acquired pneumonia, h/a, dizziness, GI
metabolism: CYP2C19 & 3A4
are PPIs or H2RAs better at immediate sx relief? why?
H2RAs b/c they immediately neutralize acid
what site of action do PPIs and H2RAs act at?
what populations is lactose intolerance more common in?
black and asian populations
mechanism of simethicone? is it absorbed? used for what?
use to tx gas
MOA: inert silicone polymer, "de-foaming" agent, reduces surface tension of gas bubbles
simethicone has been known to decrease what other medication?
thyroid products (levothyroxine)
MOA of activated charcoal? safety and efficacy? absorbed? interactions? used to tx what?
MOA: absorptive, also adsorptive so can bind up vitamins
may significantly impact absorption of medications b/c adsorptive
used to tx dyspepsia and gas
MOA of alpha-galactosidase? safe? avoid in what pts?
MOA: mold-derived enzyme which cleaves oligosaccharides before reaching colonic bacteria, recommended for gas prevention in high fiber diets
avoid w/DM and galactosemia
a pt wants an OTC flatulence product that won't interfere w/his medications and won't worsen his DM; what would you recommend?
no charcoal b/c could affect absorption of meds
no alpha-galactosidase b/c could worsen diabetes