Gastroentergology Part 1 Flashcards
anti-reflux barrier?
lower esophageal sphincter
what in saliva helps neutralize acid in gastric reflux?
bicarbonate
what drugs could inhibit (or antagonize) the tonic contraction of the LES (which is a SM)?
beta blockers
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?
calcium bicarb
which antacid can cause diarrhea?
magnesium
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