Pharmacology - GI Flashcards
Gastrointestinal Drugs
● Drugs for peptic ulcer disease
○ H₂-antagonists
○ Proton Pump Inhibitors
○ Mucosal Protectant
○ Antacids
● Laxatives
○ Bulk forming
○ Surfactant
○ Stimulant
○ Osmotic
● Antidiarrheals
● Antiemetics
○ Serotonin Antagonist
○ Dopamine Antagonist
Antiulcer agents
● H₂-antagonists
○ Famotidine
○ Cimetidine
○ Nizatidine
● Proton Pump Inhibitors
○ Omeprazole
○ Lansoprazole
○ Pantoprazole
● Antacids
○ Calcium carbonate (alka-seltzer, tums)
○ Magnesium hydroxide
○ Bismuth subsalicylate (Pepto-Bismol)
● GI protectant
○ Sucralfate
H₂-antagonists
Names: Cimetidine, famotidine, nizatidine, ranitidine
ndications: Gastric and duodenal ulcers, GERD, Zollinger-Ellison syndrome, hypersecretion
of stomach acid conditions, chronic NSAID/ASA use and GI distress
Action: Block the release of histamine. Histamine is found in mast cells within GI mucosa
and causes secretion of gastric acid and pepsin when it binds with H2 receptors in the
mucosal parietal cells. When blocked, acid secretion is blocked.
Nursing considerations:
● Monitor CBC and kidney function
● Can be given with meals**
● Peak absorption of famotidine is within 2-3 hrs
● Famotidine is available OTC in lower strengths than prescription dosages. Teach clients to only
take as directed and only for a short duration.
Proton Pump Inhibitors
Names: Omeprazole, pantoprazole, lansoprazole, rabeprazole
Indication: GERD, ulcers
Action: prevents the transport of H ions into the gastric lumen by binding to
gastric parietal cells to decrease gastric acid production
Nursing Considerations:
● Administer 30-60 minutes before meal
● Report black, tarry stools
Mucosal Protectant
Names: Sucralfate
Indications: PUD, peptic esophagitis, NSAID/ASA induced GI damage
Action: Promotes healing of ulcers by providing a barrier over them. It creates a paste when
exposed to hydrochloric acid and binds to proteins that are excreted by damaged cells in
ulcerated tissue.
Nursing considerations:
* Take on an empty stomach 1 hour before meals or 2 hours after meals and at bedtime;
often given up to 4 times a day
* Don’t give within 30 min of antacids as they can decrease the effectiveness of sucralfate
* Use caution giving antacids containing aluminum to clients with kidney failure due to
aluminum toxicity
* Monitor blood sugar in diabetics as sucralfate contains sucrose
* Can decrease the bioavailability of warfarin, digoxin, phenytoin, levothyroxine, and
several classes of ABX - separate these drugs from sucralfate for at least 2 hours**
Antacids
Names: Aluminum hydroxide, calcium carbonate, magnesium hydroxide
Indication: GERD, heartburn, gastritis, hiatal hernia, peptic ulcers
Action: Neutralize gastric acidity by reacting with HCl to form water and salts
Nursing Considerations:
● Many drug interactions
○ Don’t give with tetracyclines, phenytoin, phenothiazine antipsychotics, digoxin, thyroid
hormones, etc. It binds with them and makes them not work
● Adverse Effects:
○ Constipation w/ aluminum and calcium antacids, diarrhea w/ magnesium antacids
○ Hypophosphatemia can happen with aluminum antacids
Laxatives Types
● Bulk forming laxatives
○ Methylcellulose
○ Psyllium
○ Polycarbophil
● Surfactant laxatives
○ Docusate sodium
○ Docusate calcium
● Stimulant laxatives
○ Bisacodyl
○ Castor oil
○ Senna preps (senokot)
● Osmotic laxatives
○ Polyethylene-glycol
○ Magnesium hydroxide, magnesium sulfate, magnesium citrate
○ Lactulose
Bulk Forming Laxatives
Names: Methylcellulose, Psyllium, Polycarbophil
Indication: Constipation, diverticulosis, IBS
Action: nondigestible, causing them to swell in water and form a gel which both softens
and bulks up the stool. As the stool becomes larger, peristalsis is stimulated moving the
stool through the intestine.
Nursing Considerations:
● Take with a full glass of water or juice - can cause esophageal obstruction if not
swallowed with enough fluid!
● Contraindicated in intestinal narrowing/obstruction - would make it worse!
● Soft, formed stool 1 to 3 days after beginning use
Surfactant Laxatives
Names: Docusate sodium, Docusate calcium
Indication: Constipation
Action: Lowers the surface tension of stool, causing more water to be absorbed into it -
softens the stool, making it easier for it to pass
Nursing Considerations:
● Administer with a full glass of water
● Soft stool produced 1-3 days after administration begins
Stimulant Laxatives
Names: Bisacodyl, Castor oil, Senna preps (senokot)
Indication: Opioid-induced constipation, constipation due to a slow intestinal tract
Action: Stimulate intestinal motility and increase water reabsorption in the colon
Nursing Considerations:
● Semifluid stool within 6 to 12 hours of administration
● Available PO and PR
○ PR works extremely quickly; 15-60 minutes after admin
● Discourage long term use
Osmotic Laxatives
Names: Polyethylene-glycol, magnesium hydroxide, magnesium sulfate, magnesium citrate, lactulose
Indication: Chronic constipation
Action: Draws water into the intestine causing stool to soften and enlarge,
stimulating peristalsis
Nursing Considerations:
● Soft/semifluid stool within 6 to 12 hours of administration
● Can cause dehydration - encourage increased fluid intake
● Magnesium preparations contraindicated in renal clients
● Sodium preparations contraindicated in clients with heart failure
Antidiarrheals
Names: Loperamide, Diphenoxylate and atropine (lomotil), difenoxin, paregoric
Indication: Diarrhea, reduce volume of discharge from ileostomies
Action: Opioid derivatives. Activate opioid receptors in the GI tract, decrease intestinal
motility, slow down GI tract.
Nursing Considerations:
● Most effective antidiarrheal
● Doses are very small - do not cause dependence/euphoria unless abused
○ Severe OD → Naloxone
Antiemetics Types
● Serotonin antagonists:
○ Ondansetron (Zofran)
● Dopamine Antagonists:
○ Promethazine
○ Chlorpromazine
● Antihistamines
○ Diphenhydramine (Benadryl)
○ Dimenhydrinate (Dramamine)
● Anticholinergics
○ Scopolamine:
■ Patch form, place behind ear. Wash hands after touching. Do not rub eyes after touching the
patch.
Serotonin Antagonists
Names: Ondansetron, granisetron, dolasetron, palonosetron
Indication: Nausea/vomiting
Action: Prevent serotonin from vagal stimulation from causing nausea
Nursing Considerations:
● Administer slowly
○ Fast push can cause QT prolongation and VT
Dopamine Antagonists
Names: Promethazine, Chlorpromazine
Indication: Nausea/vomiting associated with surgery, cancer, chemotherapy, and toxins.
Action: Block dopamine receptors in the area of the brain responsible for nausea.
Nursing Considerations:
● Side effects:
○ Extrapyramidal reactions
○ Anticholinergic effects
○ Hypotension
○ Sedation + respiratory depression*
● *Use with extreme cause in children. Contraindicated below 2 years old.
