GI Pharmacology 1 and 2 Flashcards
Who tends to get gastric vs duodenal ulcers?
Gastric - older females
Duodenal - younger males
What are considered the high risk vs low risk NSAIDs for causing ulcers?
High risk - indomethacin, ketoroLAC (mainly used as analgesic per sketchy), aspirin, piroxicam (think of the sox cam in sketchy)
Low risk: Ibuprofen, diclofenac, naproxen, meloxicam (more COX-2 per sketchy, thus less side effects), especially celecoxib
What are the risk factors for chronic ulcers?
Age > 60 years
Concurrent use of corticosteroids / anticoagulants
Use of several or high dose NSAIDs
What are the adverse drug reactions by all H2 receptor antagonists?
Headache, drowsiness, fatigue, can cross BBB and cause confusion and dizziness
What adverse drug effects are more specific to cimetidine?
Cimetidine - potent inhibitor of CYP450, so rarely used for this release
Also decreases renal excretion of creatinine - remember from renal
Can cause gynecomastia and hyperprolactinemia - think of boobs in sketchy and milk shooting from nose
When do proton pump inhibitors become active? What does it inhibit?
They are absorbed as an inactive prodrug and must be absorbed first and enter parietal cells through basolateral surface -> takes around a day to be come effective, and is dose-dependent
Inhibit only ACTIVE H+/K+ ATPase
What are the two recommended triple therapy regimens for H. pylori? How long should therapy last?
MOC: Metronidazole, omeprazole, and clarithromycin
or
COA: Clarithromycin, omeprazole, amoxicillin
Therapy should last 14 days
What is the quadruple therapy and when must it be used?
PPI + bismuth + tetracycline + metronidazole
Must be used if patient has a penicillin allergy or there has been past macrolide use
What is the mechanism of action of sucralfate and the adverse effect of concern?
Undergoes extensive crosslinking in ulcer base if the environment is acidic
Concern - contains aluminum hydroxide -> special care for patients who may have aluminum overload, i.e. renal failure
What is gastroparesis?
Delayed gastric emptying in absence of gastric outlet obstruction or ulceration
-> occurs when vagus nerve is damage or stomach/intestinal muscles are not functioning properly
Causes vomiting and other nonspecific symptoms cause food has nowhere to go
What conditions are especially associated with gastroparesis?
Diabetes mellitus
Surgery on stomach or vagus nerve
What two medications are used for gastroparesis and which is used most commonly? What are there mechanisms of action?
- Metoclopramide - used most commonly - D2 receptor antagonist, and 5HT4 agonist - me tickle guy hanging from the D2 ropes
- Domperidone - D2 receptor antagonist
The D2 receptor inhibits Ach release and thus motility if not blocked.
What is one thing that is better about domperidone than metoclopramide but why is it never used?
Domperidone doesn’t cross the BBB
It is never used due to QT prolongation -> another side effect of metoclopramide (think of the torsades tapes by the judge’s table)
What are the adverse effects of metoclopramide? What are the contraindications?
Increased parkinsonian effects, tardive dyskinesia. (think of the tardive dyskinesia and NMS judge’s table)
Contraindicated in small bowel obstruction (think of the sign in front) or Parkinson’s disease
What is the mechanism of action of erythromycin in the treatment of gastroparesis?
Stimulates motilin receptors in smooth muscle cells
-> intestinal peristalsis
What medications lower LES tone?
NSAIDs, estrogens, anticholinergics
What is the first-line treatment for GERD if it is intermittent or mild/moderate?
Intermittent - antacids, i.e. calcium carbonate
Mild-moderate - OTC H2RA i.e. ranitidine
What is the treatment for severe GERD?
max daily dosing of a PPI
Antacids can be used for adjunctive relief as well
What is the acute management of upper GI bleed?
Fluid resuscitation with normal saline or lactated ringers
Blood replacement with packed RBCs or fresh frozen plasma, up to 7 mg/dL of Hgb
Endoscopy within first 24 hours to see extent of damage
What is the treatment for esophageal varices vs non-variceal bleeding?
Varices - sclerotherapy and variceal ligation
Non-variceal bleeding - electrocautery and epinephrine
What medical therapy must be given following non-variceal upper GI bleed?
PPI for at least 72 hours, may be IV drip or taken orally
-> prevents rebleeding
What is the target pH needed for healing of peptic ulcers?
Probably around pH 5, must use a PPI to achieve this
What medical therapy must be given for variceal upper GI bleed?
PPI infusion, and octreotide
Mechanism - octreotide reduces portal pressures by inhibiting glucagon-mediated splanchnic vasodilation
What are the adverse effects of octreotide?
Flushing, edema, abdominal pain, NVD (lack of absorpton due to decreased CCK and digestion)
-> these symptoms may cause further mucosal damage and upper GI bleed, risk