Med classes GI- Quiz 2 Flashcards
What are the 2 main causes of peptic ulcer disease? *
- H. Pylori (H2 blockers)
- NSAIDs (PPI’s)
How is H. Pylori diagnosed?
Diagnosed:
1. EGD or serology
2. Fecal antigen
3. Urea breath tests (patient cant have antacids, PPI, or H2 for 14 days prior) WHY DO I FEEL LIKE THIS IS A TEST ?
What is the regimen of choice for H. Pylori?*
-Quadruple therapy with: Pepto-Bismol, Flagyl, Tetracycline + PPI
Second option is Triple therapy with: PPI, Amoxicillin and Clarythromycin
H2 Blockers*
-“Tidine’s”
-MOA: Act selectively on H2 receptors in the stomach, without effecting H1 receptors — they reduce the secretion of gastric acid
-Uses: PUD/ heartburn (takes longer to work but lasts longer than antacid)
Pharm: Distribute widely across body (including placenta/breast milk)
Half life: ½ life of these drugs are prolonged in renal disease—
dosage adjustments are needed
-ADE’s: Confusion in elderly
Cimetidine= gynecomastia/ galactorrhea
-Ex. Cimetidine, Famotidine, Nizatidine
-NOTE* Cimetidine is PROTOTYPE
for this family but rarely used today d/t ADE’S (inhibits many CYP 450 isoenzymes)*
Compare and contrast Cimetidine, Famotidine, and Nizatidine *
-Cimetidine= gynecomastia, CYP, warfarin phenyntoin clopidogrel cant use
-Nizatidine= Well tolerated
-Famotidine= minimal side effects, MOST potent, NO CYP
H+/K+ ATPase Proton
Pump Inhibitors (PPI’s)*
-“Prazole’s”= more effective at suppressing acid/healing ulcers than H2 blockers
-MOA: work by inhibiting the hydrogen-potassium ATPase enzyme ,the proton pump, which is responsible for the final step in gastric acid secretion.
-Uses: Gerd, esophagitis, active duodenal ulcer, Zollinger-Ellison Syndrome
Pharm: take 30-60 mins before largest meal of day
Half life: only a few hours but duration of action is long (when initiating usually 18-24 hrs to work)
-ADE’s: Increased risk of fractures with >1 year of use, prolonged acid suppression=vitamin B 12 deficiency, supplement with ca citrate, diarrhea, C diff, low mag, increased risk of PNA
-Oral agent of Omeprazole + NaHCO3
that has a faster onset of action
- Nexium, Prevacid, Protonix are IV
-Ex: Lansoprazole, Dexlansoprazole,
Omeprazole, Esomeprazole,
Pantoprazole, Rabeprazole
Prostaglandins*
-Misoprostol (Cytotec) approved for the prevention of NSAID induced ulcers
MOA: PGE-1 produced by gastric mucosa, inhibits secretion of acid and stimulates secretion of mucus and HCO3 (Cytoprotective)
-Can be used prophylactially in those who take a lot of NSAID’s and are at increased risk for ulcer
-A deficiency of prostaglandins is thought to be involved in the pathology of peptic ulcers)
-CI: DO NOT USE THIS DRUG IN PREGNANCY/CHILDBEARING AGE
-ADE: Dose related diarrhea is the most common
Antacids*
-MOA: Weak bases that react with gastric acid to form water and a salt to diminish gastric acidity
-Also decrease pepsin activity
Uses: symptomatic relief of PUD, heartburn, GERD
Pharm: Most effective AFTER meals
-Chem: Varies widely,Efficacy of an antacid depends on its capacity to neutralize gastric HCl and whether the stomach is full or empty— food delays stomach emptying, allowing more time for antacid to react and prolonging action of the medication
ADE: Aluminum hydroxide (constipation) Magnesium hydroxide (diarrhea), accumulation and ADEs can occur in those with renal disease
-Ex: Aluminum hydroxide (constipation), Aluminum hydroxide + magnesium hydroxide (diarrhea), Calcium Carbonate (constipation), Magnesium hydroxide (diarrhea),
Sodium bicarbonate (constipation or diarrhea depending on dose)
Which antacids to avoid with HF, renal failure, HTN, or constipation*
-HF= sodium bicarb (fluid retention)
-Renal=Magnesium (toxicity)
-HTN= sodium bicarb (fluid retention)
-Constipation= aluminum hydroxide
What meds can you NOT take with antacids?*
-Tetracylines
-Flouroquinolones
-Digoxin
-Warfarn
-Phenytoin
-Keoconozale
-Iron
(All these reduce absorption)
-Levothyroxine
(reduces efficacy)
Mucosal Protective Agents*
-MOA: have actions to enhance mucosal protection mechanisms—preventing mucosal injury, reducing
inflammation and healing ulcers
-Cytoprotective compounds
-Ex. Sucralfate, Bismuth subsalicylate (Pepto-Bismol)
Sucralfate*
-Forms a complex gel with epithelial cells by creating a physical barrier that protects the ulcer from pepsin and acid, allowing the ulcer to heal
-Effective to treat duodenal ulcers and prevent stress ulcers—but use is limited due to the need for multiple daily doses, drug- drug interactions.
-It requires an acidic pH for activation—should not be given with PPIs, H2B or antacids
-Well tolerated; it can bind to other drugs and interfere with their absorption
ADE: Constipation
Which GI meds are CI for pregnant women or childbearing age?*
-Misoprostal
-Tetracyclines
-Flouroquinolones
Antidiarrheals appropriate for pregnant women and children?*
-Pregnant women= Bismuth (limited use) Need oral rehydration
-Children= Loperimide (limited doses) need oral rehydration
Bismuth subsalicylate*
-NAUSEA, Heartburn, indigestion, upset stomach, DIARRHEA- hey! pepto-bismol! ;)
-Used as part of quadruple therapy to treat H. Pylori
-It has antimicrobial actions—it inhibits the activity of pepsin, increases secretion of mucous and interacts with glycoproteins in necrotic mucosa to coat and protect the ulcer
-Prevents travelers Diarrhea
-BLACK TONGUE
-Dont use in children less than 12
What 2 sites in the brainstem play a role in vomiting?*
- Chemoreceptor trigger zone [CTZ]—located outside the blood-brain barrier— can respond directly to chemical stimuli in the blood or CSF (dopamine, serotonin)
- Vomiting center—located in the medulla, coordinates the motor mechanisms of vomiting (histamine, acetylcholine)
Phenothiazines for nausea*
-MOA: These agents act by blocking dopamine receptors in the CTZ in
the brain
-Prochlorperazine [Compazine] is the PROTOYPE in this category
-Used for low or moderately emetogenic chemotherapy agents prophylactically
-Can also be used for post-op n/v and
associated with gastroenteritis
-Not approved for children < 2 years
-Another option is Promethazine [Phenergan] (used for post-operative nausea and vomiting and GI
associated nausea and vomiting; not approved in those < 2 years)
-ADE: ADEs limits high dose, prolonged use (Extrapyramidal symptoms)
5-HT3 receptor blockers for nausea*
-“Tron”
-MOA: These drugs selectively block the 5-HT3 receptors in the periphery and in the CTZ
-This is the superior choice for chemo
-Ondansetron [Zofran]—is the PROTOTYPE drug in the category
-Pharm: Are metabolized by the liver, only Zofran requires dose reduction in those with liver disease
-ADE: QT prolongation can occur with high dose Zofran
-Not recommended in children, but Zofran can be used in those 4 and older on chemo
-Ex: Dolasetron, Granisetron,
Palonosetron
Substituted Benzamides for nausea*
-MOA: work by inhibiting dopamine in the CTZ
-Metoclopramide is the PROTOTYPE
-Because of potential for EPS—this is never recommended long term or high doses
-Uses: n/v treatment of DM gastroparesis (even though lower doses are used—risk of EPS is still concern)
-Other med: Trimethobenzamide
-Used for post-op/ gastroenteritis related n/v
-Very effective, but risk of EPS limits long term use
-Not approved to be used in children
-CI= Parkinsons
NOTE* BB WARNING FOR TARDIVE DYSKINESIA WHEN USED > 12 WEEKS*
Butyrophenones for nausea*
- “peridol”
-MOA: work by blocking dopamine receptors
-Used most often for sedation for EGD and
surgery (not used
commonly for n/v because they may
prolong the QTc, now reserved for those resistant to other anti-emetics)
-Only moderately effective for n/v
-Ex: -Droperidol, Haloperidol
Corticosteroids for nausea
-“one”
-MOA is unknown—may involve
blocking prostaglandins
-Mildly/ moderately effective for chemotherapy induced n/v
-Often used in combo with other agents
-Ex: Dexamethasone,
Methylprednisolone
Substance P/Neurokinin-1 Receptor Antagonists*
-“tant”
-MOA: These drugs target the neurokinin receptor in vomiting
center and block the actions of substance P
-Usually given with dexamethasone and a 5-HT3
-Work well for the LATE phase of
chemotherapy n/v (24 or more hours after the chemo infusion)
-Have CYP34A inhibitor/inducer interactions- avoid giving with
-ADE’s: fatigue, diarrhea, abdominal pain and hiccups
-Ex: Aprepitant, Fosaprepitant injection, Netupitant, Rolapitant
What combination of meds can you give for nausea?*
- Dexamethasone + high-dose Reglan, 5-HT3 antagonists,
phenothiazines, butyrophenones or a benzodiazepine - Antihistamines (Dramamine) + with high dose Reglan to reduce EPS reactions
- Antihistamines (Dramamine) + with
corticosteroids to reduce Reglan induced diarrhea
What nausea medications are safe in pregnancy?*
-Pyroxidine (Vitamin B6) First line
-Zofran relatively safe
-Phenergan relatively safe
