Pharmacology Exam 5: Upper GI Flashcards

Terms Definitions
Peptic ulcers occur in areas of the GI tract exposed to __ and __ when there is an imbalance of aggressive vs. protective factors.
- acid and pepsin
Aggressive factors in GI Tract:
- acid- pepsin- Helicobacter pylori
Protective factors in GI tract:
- bicarbonate and mucus secretion- prostaglandin formation
Protective actions of Prostaglandins (3):
- inhibit acid production- stimulate mucus and bicarbonate secretion- stimulate vasodilation in gastric mucosa
__ and ___ (non-selective COX 1/2 inhibitors)inhibit prostaglandin synthesis and thus may lead to PUD/GERD.
Aspirin and NSAIDs
__ __ selective inhibitors, such as Celecoxib, have less incidence of causing PUD/GERD.
- COX-2 selective inhibitorsThis is FYI: drug name was not in red.
Causes of PUD and GERD:
- Aspirin/NSAIDs- Alcohol in excess- Smoking- Helicobacter pylori infection
Chronic GERD and episodic heartburn are extremely common (10%-50% of U.S.).Patients often self-medicate with over-the-counter antacids. GERD is associated with __ ___ __ of the lower esophageal sphincter, ___ gastric emptying, and impaired resistance of t
- repeated transient relaxation of LES- delayed gastric emptying- impaired resistance of the esophageal mucosa to injury
Therapeutic overall goals for PUD/GERD:
Overall goals:Relief of symptomsHealing of ulcersPrevention of recurrencePrevention of complications (hemorrhage, perforation, and obstruction)Reduce aggressive factorsHyper-acid condition, maintain stomach pH>4Eradicate H. pylori infectionIncrease protective factors
when treating PUD and GERD, the goal is to maintain a stomach pH ___ __ __.
stomach pH greater than 4
Life style changes to help with GERD/PUD:
- raise head of bed- stop smoking- decrease alcohol consumption- avoid caffeinated/acidic drinks- three balanced meals per day- do not lay down 2-3 hours after meals- stop NSAID use unless absolutely necessary
Pharmacological therapy for GERD/PUD (4):
- Proton pump inhibitors- H2 antagonists- Antacids (good for symptoms but not long term treatment)- Sucralfate
Proton Pump Inhibitors inhibit the __ __ ___ pumps, name 2:
- inhibit the H+K+ATPase- Omeprazole- Lansoprazolethese are both OTC
Drugs that end in "-prazole" are:
Proton pump inhibitors
Proton pump inhibitors are very efficacious is inhibiting __ production and promote the healing of ulcers in the __, ___, and ___.
- acid- stomach, duodenum, and esophagus
Proton pump inhibitors __ bind ___ groups on the proton pump which ____ inactivates ___ secretion.
- covalently bind - sulfhydryl groups- irreversibly inactivates- H+ secretion
Proton pump inhibitors have __ distribution to _____ in ___ cells. The pH has to __ for these drugs to be activated, then the drug gets trapped at the site of action. Proton pump inhibitors only work on __ __ __.
- selective distribution- H+K+ATPase in parietal cells- pH has to be acidic/low- only work on actively secreting pumps
Proton pump inhjibitors have short half life, but it doesn’t matter b/c once they have deactivated the pump, you have to make new pump moleculess. It takes several doses/days of proton pump inhibitor to bring down acid production. If stop proton pump in
this was in my notes. So basically takes a few doses for it to start working and it takes missing a few doses to stop working.
Proton Pump Inhibitors are actually administered as __. They are also __ coated so that the __ is not released until its in the intestines where there is a __ pH.
- prodrugs- enteric so that the prodrug- neutral PH
In the neutral pH of the intestine, the PPI prodrug is ___, __ __, and devoid of __ ___.
- stable- lipid soluble- devoid of inhibitory activity
Absorption and Action of PPIs (proton pump inhibitors):
- neutral weak base absorbed in intestines b/c of the neutral pH environment> blood stream> parietal cells in stomach> prodrug diffuses into secretory canaliculi> acid pH causes protonation and trapping of drug near proton pump
Adverse effects of PPIs:
- nausea- diarrhea- abdominal colic- headache- dizziness - skin rash
PPI drug interactions:
- PPI inhibit cytochrome p450- Omeprazole reduces metabolism of phenytoin, warfarin, and diazepam
PPIs inhibit cytochrome p450, so Omeprazole will reduce metabolism of what 3 drugs:
- phenytoin- warfarin- diazepam
Food inhibits PPI, so take PPI 30-45 minutes before you eat. But they really need to eat 30-45 minutes later to activate the pump so that the pumps will be killed off.
A patient is on PPI, when should they eat?
- 30-45 minutes after taking medication
H2 Histamine Receptor Antagonists:
- Cimetidine- Ranitidine
Drugs that end in "-tidine" are :
H2 antagonists (blockers)
H2 antagonists are used for treatment of __ and __ ulcers, ___, __ __, and ___ states. These are also used as ___ medication to reduce danger of ___ __.
- gastric and duodenal ulcers- GERD- stress ulceres- hypersecretory states- preanesthetic medication to reduce danger of aspiration pneumonitis
what drug is used as a preanesthetic medication to reduce danger of of aspiration pneumonitis?
H2 antagonists(Cimetidine/Ranitidine)
Cimetidine, a __ __, inhibits many ___ enzymes included ___, so it has a lot of drug interactions. ___ has less drug interactions.
- H2 antagonist- CYP450 enzymes- CYP3A4- Ranitidine has less drug interactions
___ and ___ stimulate histamine release from ___ __ ___. Then histamine activates the ___ ___ of receptor on __ cells and stimulates __ __ __activity and acid secretion into the lumen.
- Gastrin and Ach stimulate histamine release- from enterochromaffin-like cells (ECL)- histamine activates H2 subtype - on parietal cells- stimulates H+K+ATPase
gastrin and Ach> activate ECL cells> release histamine> H2 receptors on parietal cells> stimulates H+K+ATPase pumps> acid secretion
gastrin and Ach> activate ECL cells> release histamine> H2 receptors on parietal cells> stimulates H+K+ATPase pumps> acid secretion
H2 inhibitors block the __ pathway.
- cAMP
H2 blockers __ ___ histamine-mediated acid secretion and also blunt the response to __ and __.
- competitively inhibit- blunt the response to gastrin and Ach
Classic antihistamines are H1 blockers and do not __ __ __.
- do not inhibit acid secretion
H2 receptors blockers are highly selective for H2 histamine receptors with minimal side effects. They inhibit __, __ __, and __ acid secretion. Thus, they reduce both the __ and __ __ of gastric secretions.
- inhibit basal, food-stimulated, and nocturnal acid secretion- reduce both the volume and H+ concentration
Adverse effects of H2 blockers:
- infrequent and mild- All agents that inhibit gastric acid secretion may alter the bioavailability or rate of absorption of certain drugs secondary to changes in gastric pH.
Cimetidine is a __ __ that inhibits the activity of ___. This drug also reduces testosterone action on androgen receptors and results in __ __.
- H2 blocker- CYP450 enzymes- gynecomastia in men
Treatment for PUD not associated with H. pylori:
- PPI one hour before first and second meal for 2 months- H2 blocker at bedtime if breakthrough symtpoms- Reduce PPI to once daily until symptoms are gone
H. pylori is a __ __ __ bacteria which is found in the mucus of the luminal surface of the gastric epithelium. Both normal patients and patients with ulcers have this bacterium. Eradication of H. pylori can hasten healing from ulcers.
- gram negative rod
Triple therapy for H. pylori eradication:
- PPI twice a day- Clarithromycin twice a day (or metronidazole)- Amoxicillin twice a day (or metronidazole if patient is allergic)TAKE ALL OF THESE FOR 14 DAYS.
Quadruple Therapy for H. pylori eradication:
- PPI twice a day- Tetracycline 4 times a day- Metornidazole 3-4 times a day- Peptobismol 4 times a dayQuadruple therapy is cheaper than triple therapy, but requires more compliance. TAKE ALL OF THESE FOR 14 DAYS.
what is Prevpak:
(not in red on slides)- combination of PPI (Lansoprazole), Clarithromycin, and Amoxicillin- used to eradicate H.pylori infection
To see if a H.pylori infection has resolved, do a __ __ __ b/c this is the most sensitive test. Unresolved infections could lead to recurrence.
- stool antigen test
After 14 day treatment of H.pylori, take patient off of the ___ for one week, and then do stool antigen test. The __ can cause a false positive.
Presence of H. pylori does not necessarily equal ulcersOn average, 30% US adults have H. pyloriOlder age, greater prevalenceHigher incidence rates in lower socioeconomic classesOral-fecal route: personal hygiene, home environmentGeneticsWater supply?
Travelers should cut their dose of ___ in half b/c stomach acid protects against traveler's diarrhea.
PPI(but don't cut tablet in half b/c they are enteric coated)
Antacids therapeutic use (3):
- simple dyspepsia- adjuncts to primary therapy with PPI or H2 blockers- primary therapy in uncomplicated GERD
Antacids are weak __ that chemically neutralize acid. The goal is to raise gastric pH above __.
- bases- 4
Antacids (2):
- ALUMINUM HYDROXIDE- MAGNESIUM HYDROXIDE- Calcium carbonate- Sodium bicarbonate- Simethicone- Gaviscon
Aluminum hydroxide antacid tends to cause ___.
Magnesium hydroxide (antacid) tends to cause ___.
Most common combination of antacids and why?
- Aluminum hydroxide and Magnesium hydroxide- this combination minimizes disturbance in bowel motility
Antacids should be taken __ hour and __ hours after a meal, and at bedtime.
one three
Adverse effects of antacids:
- changes in bowel motility- alkalosis- significant effects on absorption of other drugs- DO NOT TAKE ANTACIDS WITHIN 1-2 HOURS OF OTHER DRUGS- Rebound acidity upon discontinuation
Examples of Cytoprotective Agents (2):
- Pepto-Bismol= bismuth subsalicylate- Misoprostol
Cytoprotective agents (pepto-bismol, bismuth subsalicylate) mechanism of action:
- enhances secretion of mucus and HCO3-- inhibits pepsin activity- chelates with protein at base of ulcers and forms protective barrier against acid and pepsin- may inhibit H. pylori
Cytoprotective agents are effective adjuncts for treatment and prophylaxis of __ and __ __, ___, and ___.
- duodenal and gastric ulcers- GERD- diarrhea
Pepto-bismol (bismuth subsalicylate) and Misoprostol work by ___ mucus and HCO3- production and __ pepsin activity. They chelate with proteins at the base of __ and form a protective barrier against acid and pepsin. They may also inhibit __ __.
- increasing- inhibiting- ulcers- H. pylori
Side effects of Pepto-bismol:
- black tarry stools- most bismuth is eliminated in feces- black tongue with long term use
Misoprostol is a ___ agent.
Misoprostal is a __ agent that is a slowly metabolized analogue of ___. It stimulates production of __ and __. But it causes __ in 30% of patients. This is mostly used in patients who have to use ___.
- cytoprotective - PGE1 (prostaglandin E1)- mucus and HCO3-- diarrhea in 30% of patients- who have to use NSAIDs
6 Categories of Antiemetic agents:
- 5-HT3 blockers- Neurokinin-1 blockers- D2 blockers- Antihistamine H1 blockers- Antimuscarinics- Cannabinoids
5-HT3 antagonist/blocker antiemetic drug:
5-HT3 receptors are located many places involved in the __ __ including the __ __ __. Antagonists of these receptors, like ___, are very effective inhibitors of emesis even with ___. These are most effective when combined with ___ therapy short term like
- vomiting reflex- chemoreceptor trigger zone- Ondansetron- chemotherapy- corticosteroid- dexamethasone
Ondansetron is what type of drug?
- Antiemetic 5HT3 blocker
___ is an antiemetic that is a neurokinin 1 receptor blocker.
Aprepitant is what type of drug?
- antiemetic- neurokinin 1 blocker
Aprepitant an antiemetic that blocks __ _ receptors is usually used with a ___ ___ and __ for prevention of chemotherapy induced nausea and vomiting.
- Neurokinin-1 - 5HT-3 blocker- corticosteroids
what drug combination would you use for a patient on chemotherapy to prevent nausea and vomiting?
- Ondansetron- Aprepitant- corticosteroids
Side effects of Aprepitant, a Neurokinin-1 blocker antiemetic:
- fatigue- dizziness- diarrhea
Name the drug that is an antiemetic Dopamine D2 blocker:
Metoclopramide (Reglan)
Metoclopramide is an ____ ___ ___ ___ that is also a weak ___ __.
- antiemetic dopamine D2 blocker - also a weak 5HT3 blocker(aka Reglan, what Amy was on)
Antiemetic antihistamines, which are H1 blockers (2):
- Promethazine (fyi: Phenergan)- Dimenhydrinate (fyi: Dramamine)
Antiemetic Antimuscarinic (1):
Scopolamine- patch for motion sickness
Antiemetic agent that is a cannabinoid:
- Dronabinol aka marinol delta 9 tetrahydrocannabinoid (THC)
Dronabinol is what type of drug and is used for what?
- cannabinoid antiemetic- used for chemotherapy-induced nausea and vomiting- also an appetite stimulant
Dronabinol side effects:
- euphoria- dysphoria- sedation- hallucinations
Antiemetic agent indications:
- motion sickness- vertigo- postoperative recovery- Pregnancy (note: doxylamine/pyridoxine, discontinued)- cancer chemotherapy- migraine
Promotility agents (3):
- Metoclompramide (Reglan)- Motilin- Macrolide Antibiotics: Erythromycin
Metoclopramide is a __ receptor blocker that ___ esophageal persistalsis, ___ lower esophageal sphincter pressure, and promotes gastric ___. It has __ effect on small intestine or colon.
- D2 receptor blocker- increases- increases- gastric emptying- no effect on SI or colon
Metoclopramide (Reglan) side effects:
- hyperprolactinemia- anxiety- depression- tardive dyskinesia (typically limited to 2 week course)
Motilin hormone stimulates motility.
Uses for promotility agents:
- gastroparesis, but tolerance develops- acute GI hemorrhage, promote emptying of gastric blood before endoscopy
Metoclopramide uses (2):
- antiemetic drug- promotility drug
The macrolide antibiotics such as ERYTHROMYCIN, Clarithromycin, and Azithromycin promote motility by acting on the __ receptor.
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