GIT Flashcards
1) prodrugs = inactive
2) need H+ to activate
3) enteric coated capsules (absorbed in intestines)
4) reach parietal cell
5) decrease intrinsic factor - pernicious anemia
proton pump inhibitors
1) secreted into caniliculi and activated by acid
2) irreversibly inhibit the proton pump
3) > 90% reduction in acid secretion in 24 hrs
4) heals ulcers
proton pump inhibitors
ADR:
1) hyperchloridemia with long term use can lead patient to be vulnerable to h. pylori
proton pump inhibitors
used to treat ulcers, Gerd, Zollinger Ellison syndrome
proton pump inhibitors
clopidogrel is less effective when given with proton pump inhibitor; no anti platelet activity - MI
ADR of proton pump inhibitors
decrease in acid
1) vit B12 releases from food
2) iron, Ca2+, Mg2+ absorbs decrease
proton pump inhibitors
proton pump inhibitor drugs
omeprazole and “prazoles”
most effective anti ulcer drug
omeprazole
supresses basal acid secretion
inhibits nocturnal acid secretion
taken once daily at bedtime
excreted by kidney so lower dose in renal disease
H2 receptor antagonists
treat duodenal ulcers, Gerd, Zollinger Ellison syndrome
H2 receptor antagonists
blocks H2 receptors in parietal cells & inhibit about 65% of acid secretion
H2 receptor antagonists
1) inhibits CYP450
2) inhibits breakdown of estradiol - gynecomastia & impotence in men, galactorrhea in women
3) interacts with warfarin, phenytoin, theophylline, leading to toxicity and seizures
Cimetidine - H2 receptor antagonists
H2 receptor antagonists
Cimetidine and other “tiding”
cannot be given as stand alone treatment for peptic ulcer
sucralfate
acts only if gastric pH is less than 4
speeds up healing process
sucralfate
used to treat duodenal ulcers not NSAID induced
increases healing and ulcer recurrence
needs H+ become sticky gel - cover ulcer
sucralfate
crosslinks and polymerizes HCL in stomach to form a viscous sticky gel to buffer acid
protects for up to 6-8 hrs
stimulates PGE2 production causing: increase mucus and HCO3 secretion
sucralfate
treats NSAID and corticosteroid induced peptic ulcers
misoprostol
synthetic PGE1 analog
increases mucus and HCO3
protects from ulceration as well
misoprostol
diarrhea and cramps
ADR of misprostol
Contraindications in pregnant women - increase uterine contractility - abortion
misoprostol
used to treat H pylori induced peptic ulcers
bismuth subsalicyclate
increases mucus ans prostaglandin production
protective coating over ulcer
eradicates H pylori infection
bismuth subsalicyclate
ADR: black stool, black tongue, neurotoxicity
bismuth subsalicyclate
promote upper GI motility enhance coordinated contraction of antrum and duodenum increase gastric emptying relief of gastric stasis decrease gerd antiemetic
prokinetics
contraindicated in patients with bowel obstruction
prokinetics
muscarinic agonist
increases GI motility
bethanechol
AchE inhibitor
increases GI motility and inhibits Ach degradation
neostigmine
D2 selective antagonist = antiemetic
5HT4 receptor agonist = increase GI motility
crosses BBB
metoclopramide
treats nausea usually associated with chemotherapy and gastroparesis
metoclopramide
hyperprolactinemia, extra pyramidal effects, tardive dyskinesia
metoclopramide
D2 selective antagonist = antiemetic
does not cross BBB
can be given to Parkinson’s pts
domperidone
used to treat: nausea associated with chemo, gastroparesis, stimulates milk secretion in women in pregnancy
domperidone
hyperprolactinemia and less CNS effects
domperidone
serotonergic agonist - activates 5HT4, inhibits 5HT3
cisapride
No D2 activity = No CNS side effects, no hyperprolactinemia
cisapride
increase GI motility, hyper motility of colon, not antiemetic
cisapride
used to treat constipation
cisapride
blocks IKR K+ channels in GIT and heart
cisapride
causes ventricular arrhythmia by TDP when combined with CYP450 inhibitors like ketaconazole, macrolides
cisapride
5HT4 agonist
increase GI motility
mosapride
macrolide antibiotic
motion agonist - peptide hormone (secreted from M cells in GI)
increases gastric emptying
increases duodenal contraction
Erythromycin
used to treat: diabetic gastric paresis, causes autonomic neuropathy leading to constipation
Erythromycin
