GI drugs Flashcards
(26 cards)
Cimetidine, ranitidine, famotidine
H2 receptor antagonists
block Histamine from ECL cells
not as effective as PPI (70%)
Tx: nocturnal acid secretion, duodenal ulcers (4-8 weeks) zollinger-ellison sydrome (increased gastrin secretion)
renal metabolism via organic cation system
AE (
misoprostol
synthetic PGE2 decreased food induced acid (80-90%) short 1/2 life (3 hours) used to prevent NSAID injury AE Diarrhea, exacerbation of IBD, uterine contraction (abortion)
Sucralfate (carafate)
octasulfate of sucrose with Al(OH)3 forms pH neutral protective film acid activated (take before food, no antacids or PPI) tx stress ulcers (duodenal> gastric) AE constipation, blocks drug absorption
antacid
Al(OH)3- slow acting, slow motility-constipation
Mg(OH)2- fast acting, speeds motility (CCKr)- contraindicated in renal disease
CaCO3- hypercalcemia
last 2-3 hours with food
AE rebound acid secretion, may block drug absorption (space by 2 hours)
pirenzepine
Muscarinic antagonist (m1 specific)
block ACh at intramural ganglia causing decreased vagal response
block stimulation of parietal and ECL cells
decrease acid by 40-50%
AE: significant anticholinergic effects (rarely used)
tegaserod
5-HT4 partial agonist
Prokinetic
for females
tx IBS, chronic constipation and bloating
AE-fatal cardiac arrhythmias (restricted distribution program)
cisapride
5-HT4 receptor agonist and adenylate cyclase stimulant
prokinetic
tx GERD and gastroparesis
AE fatal cardiac arrhythmias
bethanechol
M2 and M3 cholinergic agonist
prokinetic
AE bradycardia, flushing, diarrhea, cramps, salivation, blurred vission
Neostigmine methylsulfate
AChEI
prokinetic
tx An Ileus
metoclopramide
D2 antagonist, some 5-HT3 antagonist
prokinetic
Tx increase LES tone, upper GI motility, relieve GERD, antiemetic with chemotherapy, laxative
AE extrapyramidal signs (dystonias, parkinson’s like, tardive dyskenesia)
erythromycin, oleadomycin, azithromycin, clarithromycin
macrolides
prokinetic (imitate motilin)
lead to gastric dumping (may be pxful)
tx: move bezoars, scleroderma, pseudo-obstructions
lactulose, sorbitol, mannitol
osmotic laxative
sugars
tx constipation with opioids and vincristine; decreases intestinal pH to trap NH4-> liver disease
glycerin
laxative
suppository
hydroscopic and lubricant- increases water retention leading to peristalsis
docusate
stool wetting agents, stool softeners
do not increase frequency
surfactants that promote fat stool mixing
bisacodyl
irritant laxative
PO or PR
not to chew or take with milk/antacids
castor oil
smooth muscle stimulation–> increased small bowel motility
methyl cellulose, psyllium, polycarbophil
bulk forming laxative fiber laxative bulk increases peristalsis tx regular soft stools AE: exacerbate intestinal obstructions, absorb other drugs
bismuth
antidiarrheal
anti secretory, anti inflammatory, anti microbial
H. pylori tx
alosetron
5-HT3 antagonist antidiarrheal tx IBS diarrhea (acts opposite 5-HT4) AE constipation with fatal ischemic colitis
ondansetron, granistron, dolasetron, palonosetron
5-HT3 antagonist; act on CTZ, NTS and peripheral small intestine antiemetic liver metabolism (except palonosetron) AE constipation, diarrhea, HA, light headed
prochlorperazine, chlorpromazine
phenothiazines
D2 receptors in CTZ and H1 receptors (cerebellum)
tx motion sickness, antiemetic (not as affective for chemo as metoclopramide)
AE extrapyramidal signs, dissociative dysphoria
cyclizine, promethazine, hydroxyzine, diphenhydramine
antihistamine, cerebellum and NTS
tx antiemetic and motion sickness
cyclizine- anticholinergic -> for abdominal CA
scopolamine
muscarinic ACh receptor antagonist (vestibular apparatus)
transdermal patch
tx motion sickness, post surgical antiemetic
AE dry mouth, blurred vissioin
behavioral issues with px or anxiety
syrup of ipecac
emetic
acts on CTZ
