GI therapeutics Flashcards
3 target sites of acid production
- histamine - receptor on parietal cell - cAMP pathway
- Ach - receptor on parietal cell - Ca pathway
- gastrin - receptor on par. cell - Ca pathway
final target in all 3 therapies
proton pump - H out for K in
4 antacids and their SEs
- aluminum - accumulates, constipation
- magnesium - diarrahea, accumulates in renal issues
- Mg-Al mix (maalox) - more potent and had competing bowel effects
- Ca (tums, rolaids) - stones, constipation
names of histamine (H2) blockers
____-idine
issue with H2 blockers
when block histamine, gastrin takes over and produces more acid - give intermittently
when to give proton pump inhib
right before meal
how does proton pump inhb. work
block H/K ATPase by binding irreversibly
names of proton pump inihibitor
______-prazole
what is special about dexlansoprazole
enteric coating allows to realease at diff. times
common SE of PPIs
headache, diarrhea, nausea, dizziness
2 types of smooth muscle relaxants (antispasmotic)
- L-type Ca - channel blockers - has CV side effects
2. nitroglycerin - converts to NO and relaxes smooth muscle
what are anticholinergics and their SEs
Ach receptor blockers (buscopan)
SE - blurry vision, tacycard, urine retention
GI Sx of functional bowel disease (visceral hyperalgesia
abdo pain, bloating, dyspepsia, heightened senstivity
2 psychotrpics for visc, hyperalgesia
- TCA (amytriptyline, desipramine) - anticholinergic
- SSRI (citalopram, fluoxitine)
both lower than therapeutic doses
where does nausea sensation come from
vomiting center in cortex
what is area postrema
zone outside BBB that samples contents of blood
3 areas that feed into vomiting center and what they signal with
- chemorecptor zone -D2 and 5-HT3
- Vagus and GI - 5-HT3
- vestibular app - H1 and Ach
what does gravol work on
H1
what does ondansteron work on
5-HT3
what is metoclopramide
prokinetic and anti-emetic
how does metoclopramide work
D2 antagonist, weak 5HT3 antag, 5HT4 agon
- releases Ach and prokinetic to esoph to prox. jejunum
what are SE of metaclopramide
D2 antag effect - parkinsonian
what is option to metacloprimide and why is it better
domperidone - doesn’t cross BBB
what is erythromycin
antibiotic that acts on motilin receptors of SMC and ach neurons
what does it do
inits. MMC in upper gut and reduces fundic volume
