what dz are we talking about for “acid-peptic dz”
GERD
Gastric/duodenal ulcers
non-ulcer dyspepsia
stress related gastritis
causes of PUD
list the tx approaches for PUD
pneumonic for tx PUD
Acid.. decrease it
Protect…gastric mucosa
Eradicate HP if tests +
6 agents used for PUD
H2 rec antags PPI Antacids Prostaglandins Mucosal protectors anti-microbials
List the H2 receptor antagonists
*ending?
-tidine
Cimetidine
Famotidine
nizatidine
ranitidine
what stimulates gastric acid secretion? (3)
ACH
histamine
Gastrin
MOA for H2 blockers
explain what happens after ACH histamine and gastrin bind to stomach receptors
Percent that H2’s reduce gastric acid
70%
direct and indirect pathways for H2 rec antags
DIRECT: ACH, gastrin and histamine stimulate parietal cell–trigger release of H+ into stomach lumen
INDIRECT: ACH and gastrin also stimulate enterochromaffin-like cells (ECL)–>result in secretion of histamine–>then histmaine also acts on parietal cell
indications for H2 receptor antags
PUD (w/o HP)
stress ulcers
GERD
Pharmkinetics for H2 receptor antags
well absorbed
peaks in 1-3 hours
short half life
excreted by kidneys
time of day to take H2 antags
at night or in fasting state
NSAID induced ulcers–PPI or H2 blockers work best? why
PPI
*helps heal and prevent future ulcers better than H2
high or low tolerance for H2 recep blockers
High **
so it is common for s/s to return after a few days of tx
Cimetidine:
-drug to drug rxns high or low? and why
HIGH since it is CYP450 isoenzyme inhibitor
what drugs interact heavily with Cimetidine (10)
INCREASES levels of:
Famotidine routes of admin
IV or PO
which H2 blocker was removed by FDA in 2020 and why
Ranitidine
*low levels of nitrosamine impurity was found
Nizatadine also removed by FDA
H2 rec antags and ketoconazole
WHY?
Concomittant use can reduce effectiveness of ketoconazole
*for ketoconazole to work— it needs to be in an acidic envi and H2 blockers reduce the acidic envir
Absorption of H2 rec blockers is reduced or increased by __% when given with ____?
REDUCED
10-20%
Antacids
do H2 blockers go into Breast milk?
yes
do H2 blockers cross placenta?
yes