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DH206: PHARMACOLOGYCHAPTER 15 GI DRUGSLisa Mayo, RDH, BSDH
GI Drugs
HCl formation in stomach occurs in parietal cellsof the stomach (pH=1.0-2.0)
HCO3- leaves parietal cell
Cl- enter parietal cell & combo with H+ = HCl
Gastrointestinal Drugs
GI Diseases
1. Gastroesophageal reflux disease (GERD)
2. Peptic ulcer disease (PUD)
3. Chronic inflammatory bowel: Ulcerative colitis, Crohn’s
4. Constipation
5. Diarrhea
6. Nausea & Emesis(vomiting)
**The GI tract is highly susceptible to emotional changes because it is innervated by the
VAGUS nerve associated with the ANS**
1. Gastroesophageal Reflux Disease
• GERD, or “heartburn,” is the most prevalent GI disease in U.S.• Stomach contents flow back up into the esophagus through the
cardiac sphincter which is not functionally correctly• Irritation, inflammation, erosion occur because esophagus not
designed to handle the levels of acids in the stomach• Pain may be severe & felt in middle of chest
1. Gastroesophageal Reflux Disease
• Risk factors• Alcohol use• Smoking• Spicy foods• Stomach ulcers• Meds: Aspirin, NSAIDs, CCB, Fosamax, Tetracycline
• Symptoms exacerbated by:• Supine position• Large meals
• Long-term complication = Barrett’s esophagus
1. Gastroesophageal Reflux Disease
Treatment• Lifestyle changes
• Avoid eating for 4 hours prior to bed• Eat smaller meals• Pillow while sleeping
• Drugs therapy
1. Antacids
2. H2-antagonists
3. Proton-pump inhibitors (PPIs)
4. GI stimulants
2. Peptic Ulcer Disease (PUD)
• Peptic ulcer: circumscribed loss of tissue or break that occurs in the GI mucosa extending through the smooth muscle that lines the GI tract
• Occurs when imbalance of:1. Gastric acid 2. Pepsin3. Mucosal defense factors prostaglandins
• Dental Management: p.187, Box 15-1• Etiology
1. Helicobacter pylori (gram (-) & alters inflammatory response)
• Combo Tx of 2 ABX + H2-blocker/PPI 2. Long-term aspirin/NSAID or corticosteroid use
2. Treatment PUD
1. Same as GERD plus:
2. Prostaglandins
3. Protective barriers
4. ABX: H.pylori
NBQ
Which of the following risk factors are primarily involved in causing peptic ulcer disease?
a. Smoking & alcohol
b. Caffeine & smoking
c. H.pylori and NSAIDs
d. S.mutans and alcohol
NBQ
Which of the following risk factors are primarily involved in causing peptic ulcer disease?
a. Smoking & alcohol
b. Caffeine & smoking
c. H.pylori and NSAIDs
d. S.mutans and alcohol
3. Chronic Inflammatory Bowel Disease (IBD)
2 categories of inflammation1) Ulcerative colitis: sores in mucosal of colon/rectum2) Crohn’s Disease: inflammation spreads deep into
affected tissues
• Smoking cessation may exacerbate
3. Chronic Inflammatory Bowel Disease (IBD)
DRUGS FOR TX
FIBER SUPPLEMENTS 1st
ANTIINFLAMMATORY Sulfasalzine(Azulfidine) Mesalamine(Apriso) Balsalazide(Colazal) Olsalazine(Dipentum)
CORTICOSTEROIDS Prednisone
IMMUNOSUPPRESSANT 6-mercaptopurine(Purinethol) Azathioprine(Imuran) Cyclosporine
ANTIDIARRHEAL Imodium
ANTISPASMODICS Anticholinergics
TNF-ALPHA NUETRALIZER Infliximab(Remicade)
4. ConstipationRisk factors
1) Narcotics2) Anticholinergics3) CCB4) Aluminum-containing antacids5) Iron products
Agents Drugs
Bulk-forming laxatives Methycellulose, polycarbophil, psyllium
Watery evacuation (osmotic/saline laxative)
Magnesium
Lubricant Mineral oil
Soften stool/Emollients Disacodyl sodium sulfosuccinate
p.190
5. DiarrheaEtiology• Most common bacterial causes: Salmonella, E.coli• ABX: broad-spectrum most common• NSAIDs, Diuretics, Antihistamines (H2-inhibitors), Digoxin
DRUGS NOTATIONS
Ioperamide(Imodium)
Diphenoxylate + Atropine (Lomotil)
Opiate + Anticholinergic
Bismuth subsalicylate(Pepto-Bismol, Keopectate)
Traveler’s diarrhea (NBQ)
Yogurt or acidophilus Use when on broad-spectrum ABXYogurt 2hrs before tetracycline (NBQ)
NBQ
All of the following drugs reduce GI motility and are used to treat diarrhea EXCEPT which one?
a. Loperamide(Imodium)
b. Bismuth subsalicylate(Pepto-Bismol)
c. Furosemide(Lasix)
d. Diphenoxylate and atropine(Lomotil)
e. Attapulgite(Kaopectate)
NBQ
All of the following drugs reduce GI motility and are used to treat diarrhea EXCEPT which one?
a. Loperamide(Imodium)
b. Bismuth subsalicylate(Pepto-Bismol)
c. Furosemide(Lasix) Loop diuretic for HBP
d. Diphenoxylate and atropine(Lomotil)
e. Attapulgite(Kaopectate)
NBQ
Which of the following drugs has the potential to cause severe diarrhea?
a. Clindamycin
b. Ciaspride
c. Diazepam
d. Metronidazole
e. Vancomycin
NBQ
Which of the following drugs has the potential to cause severe diarrhea?
a. Clindamycin
b. Ciaspride
c. Diazepam
d. Metronidazole
e. Vancomycin
6. Nausea & Emesis• NO Clindy• Drugs used to tx
1) Anticholinergic2) Antiemetic3) Depress chemoreceptor trigger zone4) Cannabinoids
DRUG CLASS DRUGS
Phenothiazide Phenergan, Compazine
Anticholinergic Dramamine, Bonine
Block chemoreceptor trigger zone Zofran, Anzemet, Tigan
I Promise I Won’t Do This to You!!!
Drugs Used to Treat GI Diseases
Acid Neutralizers1. Antacids
Antisecretory Drugs: Receptor-Mediated Drug Action2. Antihistamines (H2-blocking agents)3. PPIs4. Prostaglandins5. GI stimulants
Protective Barrier Drugs6. Sucralfate(Carafacte)
Drugs Used to Treat GI Diseases
Acid Neutralizers1. Antacids
Antisecretory Drugs: Receptor-Mediated Drug Action2. Antihistamines (H2-blocking agents)3. PPIs4. Prostaglandins5. GI stimulants
Protective Barrier Drugs6. Sucralfate(Carafacte)
Acid NeutralizersAntacids
Used to relieve the pain & indigestion Many brands OTC: magnesium, aluminum, calcium Oldest antacid: sodium bicarb (Alka-Seltzer) but can create
alkalosis, cannot be used by cardiac patients Pepto-Bismol: used in tx PUD
P.189
Acid Neutralizers
Antacid Use
Calcium carbonate(Tums, Maalox) GERD
Magnesium hydroxide(Milk of Magnesium) GERD
Aluminum/magensium hydroxide/simethicone(Maalox, Mylanta) GERD
Calcium carbonate/magensium hydroxide(Rolaids) GERD
Sodium bicarbonate (Gaviscon) GERD
Bismuth subsalicylate(Pepto-Bismol) PUDH.pylori
Acid NeutralizersAntacids
Action: Basic saltsNeutralize HCl acids in stomach Raise pH of stomach
Can alter absorption of MANY other drugs Short duration (30min)
Guidelines for Patients
Antacids taken 2hrs prior to tetracycline (CH7)
Hypertensive pt’s: avoid sodium-based antacids
NBQ
Which of the following GI drugs should not be given concurrently with doxycycline?
a. Omeprazole
b. Cimetidine
c. Antacids
d. Lansoprazole
NBQ
Which of the following GI drugs should not be given concurrently with doxycycline?
a. Omeprazole
b. Cimetidine
c. Antacids
d. Lansoprazole
Drugs Used to Treat GI Diseases
Acid Neutralizers1. Antacids
Antisecretory Drugs: Receptor-Mediated Drug Action2. Antihistamines (H2-blocking agents)3. PPIs4. Prostaglandins5. GI stimulants
Protective Barrier Drugs6. Sucralfate(Carafacte)
Drugs Used to Treat GI DiseasesAntisecretory Drugs: Receptor-Mediated Drug Action
1. Antihistamines (H2-blocking agents)2. PPIs3. Prostaglandins: Misoprostol4. GI stimulants: Metoclopramide
P-450 inhibitors – MANY drug interactions
Parietal cell are the site of action of Antihistamines, PPI, Prostaglandins
Drugs Used to Treat GI Diseases
Antisecretory Drugs: Receptor-Mediated Drug Action1. H2-blocking agents
Histamine ReviewHistamine located in GI mucosa within mast cellsHistamine Receptors (called H2-receptors)
Mediate secretion of gastric acid & pepsinLocated in parietal cells of the GI system (parietal cells produce acids)
H2 stimulation = parietal cells release more acids (↓pH)
If block receptors: reduce acid & pepsin production
Parietal cells (secrete
histamine)Site of action of antihistamines
↓Reduce acid &
pepsin production
Drugs Used to Treat GI DiseasesAntisecretory Drugs: Receptor-Mediated Drug Action
1. Antihistamines• Inhibit P-450 – interact with MANY drugs (NBQ)• Similar onset of action to antacids (quick) but longer duration of
action• Uses: PUD & GERD
Antihistaminescimetidine(Tagamet) PROTYPE Drug interactions due to CYP1A2 liver
metabolismDo NOT use more than 6wks (agranulocytosis, diarrhea)
Ranitidine(Zantac)
Famotidine (Pepcid, Mylanta AR)
Nizatidine(Axid)
All end in ~tidine
Drugs Used to Treat GI Diseases
Antisecretory Drugs: Receptor-Mediated Drug Action2. PPIs
• Drug of choice for patients with daily symptoms or those not responding to antihistamines
• Reduce peak acid output• Achieve almost total suppression of acid secretion because they
bind irreversibly to parietal cells• Many drug interactions (P-450 inhibition) (NBQ)
Guidelines for Patients
Valium & Dilantin interactions
No aspirin
Xerostomia
Drugs Used to Treat GI Diseases
Antisecretory Drugs: Receptor-Mediated Drug ActionPPIs
PPIs
Omeprazole(Prilosec) PROTYPE
Omeprazole/sodium bicarbonate(Zegerid)
Lansoprazole(Prevacid)
Esomeprazole(Nexium)
Rabeprazole(AcipHex)
Pantoprazole(Protonix)
Rabeprazole(AcipHex)
Drugs Used to Treat GI Diseases
Antisecretory Drugs: Receptor-Mediated Drug Action3. Prostaglandins: Misoprostol(Cytotec)
• Synthetic prostaglandin (PGE2α)
• Management of NSAID/Aspirin-induced ulcers• Inhibits gastric acid secretions• Increases gastric mucosal defenses• Pregnancy category X
p.189
Drugs Used to Treat GI DiseasesAntisecretory Drugs: Receptor-Mediated Drug Action
4. GI stimulants: Metoclopramide(Reglan)• Stimulates contraction of the lower esophageal sphincter by
enhancing action of ACH (acetylcholine)
↓• Decrease reflex gastric juices back into esophagus• GERD ONLY, not PUD
NBQWhich 3 GI drugs below reduce the formation of stomach acid by inhibiting the proton pump of the stomach parietal cells?
a. Ranitidine(Zantac)b. Esomeprazole(Nexium)c. Famotidine(Pepcid)d. Omeprazole(Prilosec)e. Lansoprazole(Prevacid)
NBQWhich 3 GI drugs below reduce the formation of stomach acid by inhibiting the proton pump of the stomach parietal cells?
a. Ranitidine(Zantac)b. Esomeprazole(Nexium)c. Famotidine(Pepcid)d. Omeprazole(Prilosec)e. Lansoprazole(Prevacid)
Drugs Used to Treat GI Diseases
Acid Neutralizers1. Antacids
Antisecretory Drugs: Receptor-Mediated Drug Action2. Antihistamines (H2-blocking agents)3. PPIs4. Prostaglandins5. GI stimulants
Protective Barrier Drugs6. Sucralfate(Carafacte)
Barrier Enhancer
Sucralfate(Carafate)• Complex of aluminum hydroxide + sulfated sucrose• “Bandage” over ulcer• PUD short-term tx• Forms a protective barrier over damaged mucosa, binds to
PRO in ulcers• Inhibits the action of pepsin• Absorbs bile salts that can cause irritation of the gastric
lining• Most common side effect: constipation
Summary Tx for PUD/GERD
PUD TX2 ABX + Antihistamine + Antacid
GERD TXAntacid + Antihistamine/PPI
NBQ
Which of the following drugs is best for starting initial treatment of mild, intermittent heartburn?
a. Sodium bicarbonate/alginic combination
b. Cimetidine
c. Omeprazole
d. Lansoprazole
NBQ
Which of the following drugs is best for starting initial treatment of mild, intermittent heartburn?
a. Sodium bicarbonate/alginic combination
b. Cimetidine
c. Omeprazole
d. Lansoprazole