Pharmacology - Drugs Acting on GI Tract (Exam 4) Flashcards
Functions of GI tract
Digest/absorb ingested nutrients
Excrete waste products of digestion
GI diseases often present with _______ ___________
oral manifestations
GI related drug for treating Xerostomia
Sialagogues (cholinergic agonists)
GI related drug for short term control of salivary flow in dental procedures
Antisialoagogues (anticholinergics)
GI related drug for treating nausea and vomiting
Antiemetics
(antihistamines, D2 antagonists, cannabinoids)
Name 2 causes of nausea and vomiting in dentistry
- Swallowing blood after oral surgery
- Opioid analgesics during and post surgery
Acid peptic diseases are caused by damage in GI mucosa from ____________ and ___________ (ON EXAM)
gastric acid and pepsin
2 most common acid peptic diseases
- GERD (gastroesophageal reflux disease)
- PUD (peptic ulcer disease)
What is the major component of digestive fluid produced in the stomach?
Hydrochloric acid (HCl)
pH of stomach acid
1-2
Hydrochloric acid is secreted through the? (ON EXAM)
Proton pump (H+/K+ ATPase)
Which cells is the proton pump (H+/K+ ATPase) found in?
Parietal cells
Which cells produce hydrochloric acid?
Parietal cells
(H+/K+ ATPase proton pump is in parietal cells!)
Name 3 local and systemic endocrine effects that control and stimulate the proton pump (ON EXAM)
- Gastrin
- Histamine
- ACh
Most common symptom of GERD
Heartburn
What is GERD caused by?
Abnormal reflux of gastric contents retrograde through cardiac sphincter into esophagus
What is peptic ulcer disease caused by? (ON EXAM)
Helicobacter pylori infection (main cause)
Extended use of NSAIDS (less common)
Primary complication of peptic ulcer disease
Hemorrhage
T/F: antacids are weak acids
False! They’re weak bases
What happens if you take too many antacids?
Affects absorption of other medications by directly binding to the drug or altering the drug’s solubility
What drugs can antacids affect?
Antifungals (ketoconazole, itraconazole)
Antibiotics (tetracycline, fluoroquinolone)
H2 receptor antagonists can inhibit up to _____ of total 24-hr acid secretion
70%
Example of mucosal protective agents
Pepto bismol (bismuth subsalicylate)
Sucralfate
What does pepto bismol protect against?
Ulcers and erosions
What does pepto bismol treat?
Acute nonspecific diarrhea
What does pepto bismol reduce in acute diarrhea?
Stool frequency
Liquidity
What does pepto bismol bind to?
Enterotoxins
T/F pepto bismol has some antimicrobial effects
True
What is sucralfate a complex of?
Aluminum hydroxide + sulfated sucrose
T/F sucralfate provides a mechanical barrier over the surface of a gastric ulcer
FALSE, it provides a physical barrier over the surface of a gastric ulcer
Drug class of choice for peptic ulcer disease and GERD
Proton pump inhibitors
PPIs are __________ (longer/shorter) lasting and ________ (more/less) potent than H2 blockers
longer; more
Proton pump inhibitor suffix
“-prazole”
H2 receptor antagonist suffix
“-tidine”
Main difference between PPIs and H2 antagonists
PPIs: IRREVERSIBLY inhibit proton pump
H2 antagonists: REVERSIBLY inhibit H2 receptor
Which drug slows the metabolism of lidocaine and benzodiazepines, and is a potent inhibitor of cytochrome P450 enzymes?
Cimetidine
3 adverse effects with long term PPI use
- Alters normal gastric pH
- Alters medication absorption
- Impacts metabolism of medications by CYP450
What is the mechanism of prostaglandins?
Bind to parietal cell receptor to decrease acid secretion
Stimulate mucus and bicarbonate secretion to inhibit acid secretion
Contraindications of prostaglandins
Pregnancy
How do we treat an H. pylori infection?
Triple regimen of a PPI with two antibiotics (clarithromycin + amoxicillin/metronidazole)
What is the effectiveness of the triple regimen being influenced by?
Growing incidence of bacterial resistance to clarithromycin
What treatment is recommended in areas of high resistance and in cases where clarithromycin-based therapy has failed in treating H. pylori infections?
Quadruple therapy
(PPI/H2 blocker + pepto bismol + metronidazole + tetracycline)
These drugs should be avoided in patients with an ulcer
Corticosteroids
What should NOT be used for pain management of pts with PUD? Why?
Aspirin and Ibuprofen
They’re NSAIDS
What drugs are used for chronic idiopathic constipation?
Linaclotide and Plecanatide
Lubiprostone
Prucalopride
Lactitol
What drugs are used for chronic idiopathic constipation and IBS-C?
Linaclotide and Plecanatide
Lubiprostone
What kind of drugs are Linaclotide and Plecanatide, and what do they do?
Guanylate cyclase-C agonists
Increase fluid secretion and muscle movement
What kind of drug is Lubiprostone, and what does it do?
Cl- channel activator
Increases fluid secretion
What kind of drug is Prucalopride, and what does it do?
Serotonin receptor agonist
Has prokinetic activity and increases peristalsis
What kind of drug is Lactitol, and what does it do?
Non-absorbable disaccharide
Sweetener in food, laxative, and increases peristalsis
Gastroparesis is most common in pts with?
Diabetes mellitus
Name 2 GI stimulants that can treat gastroparesis
Metoclopramide (antiemetic activity)
Erythromycin
Difference between IBS and IBD
IBS: intestinal disorder where we do NOT know the cause
IBD: intestinal disorders with severe inflammation and bleeding and damage to GI tract
What do medications for IBS-C do?
Increase fluid secretion in intestine
What are 2 types of IBD?
Crohn’s disease
Ulcerative colitis
Pts with IBD are at increased risk of developing caries and oral infections. Why?
IBD treatment involves suppressing the immune response which leads to more infections and caries
Avoid prescribing _________ for IBD pts because they may trigger a flare-up
NSAIDS
What does sucralfate reduce the absorption of?
Tetracycline
What drugs are opioid derivatives?
Diphenoxylate
Loperamide
What is the mechanism of Diphenoxylate and Loperamide?
Mu-opioid receptor agonists
Decrease motility
What do Diphenoxylate and Loperamide treat?
Acute nonspecific diarrhea
Which opioid derivative is available OTC since it does not cross BBB or cause addiction?
Loperamide
Which drugs antagonize Metoclopramide’s prokinetic activity in the GI tract?
Opioids
Anticholinergics