Gastrointestinal drugs Flashcards
What kind of drug is ranitidine?
Histamine-2 receptor antagonist
How does Ranitidine work?
Blocks H2 receptors on the parietal cells of the stomach to reduce the volume of gastric juice and decreases concentration of acid
Nursing assessments for H2 antagonists
Assess for epigastric pain, and pain or signs of GI bleeding (hematemesis, frank blood, or occult blood in stool)
Assess for signs of confusion
Administer antacids an hour apart from other medications
Monitor for signs of pneumonia
What kind of drug is Omeprazole?
Proton Pump Inhibitor
How does Omeprazole work?
Causes irreversible inhibition of H+, K+ ATPase, the enzyme that generates gastric acid
A single dose inhibits acid production by 97% in 2 hrs
Adverse effects of Omprazole
MINOR
Headache
Diarrhea
N & V
SEVERE
Pneumonia
Fractures
Rebound acid hypersecretion dyspepsia
Hypomagnesemia
Nursing considerations for Omeprazole
Administer doses before meals
Monitor serum Mg with prolonged use
Monitor for signs of pneumonia
Monitor for fractures
How does Sucralfate work?
Protects against ulcers by creating a mucosal barrier against acid and pepsin
Undergoes chemical reaction in acidic environment of stomach to form a sticky gel
Adheres to ulcer for 6 hours
Eliminated in the feces
Oral administration only
Adverse effects of sucralfate
Constipation (rare)
No systemic side effects because not absorbed
Nursing considerations for sucralfate
PO only
Should not be taken within 30 min of antacids
Can alter absorption of many other meds: should be taken 2hrs apart
Misoprostol description
Replaces endogenous prostaglandin
Suppresses secretion of gastric acid
Promotes secretion of bicarb/ mucus
Increases mucosal blood flow
Misoprostol indication
Limited to prevented NSAID induced gastroduodenal ulcers
Often seen as a combo drug w/ NSAIDs
Misoprostol adverse effects
Minimal
Diarrhea
Nursing considerations for misoprostol
Contraindicated in pregnancy - will cause spontaneous abortion
Antacids description
Alkaline compounds that neutralize stomach acids
Raise pH of stomach above 5
Reduce pepsin activity
Stimulate production of prostaglandins
Not systemically absorbed
Indications of antacids
GERD, PUD, and gastritis
Examples of antacids
Magnesium hydroxide (MOM), Aluminum hydroxide, Calcium carbonate (TUMS), sodium bicarbonate
Adverse effects of magnesium hydroxide
AKA Milk of Magnesia
Diarrhea (often administered with aluminum hydroxide to counteract this effect)
Avoid in patients with undiagnosed abd. pain
Mg can accumulate in people with renal dysfunction
Adverse effects of aluminum hydroxide (Almajel)
Constipation
High affinity for phosphate (can cause hyperphosphatemia)
Adverse effects of Calcium carbonate (TUMS)
Constipation, belching, flatulence (release CO2)
Risk for acid rebound
Calcium can accumulate in kidney failure (not recommended)
Adverse effects of Sodium Bicarbonate
Belching, flatulence (releases CO2)
In renal failure can cause systemic alkalosis
High risk of sodium loading (dangerous for HTN, HF)
Nursing considerations for antacids
Monitor GI function (constipation/ diarrhea)
Monitor electrolytes
Hypermagnesia, hyperphosphatemia, hypercalcemia
Give after meals
Unpleasant to digest therefore adherence is difficult
Drugs for PUD
Amoxicillin
Metronidazole
Clarithromycin
Tetracycline
Example of bulk-forming laxative
Psyllium
Psyllium description
Similar action to finer (increased bulk to soft formed stool)
Made of polysaccharides and cellulose derived from grains and plants (non digestible)
Note absorbed systemically
Should be administered with large glass of water to avoid obstruction/ impaction
Indications for psyllium
Chronic constipation, prevent straining of stool, IBS
What kind of laxative is lactulose?
Osmotic laxative
Lactulose description
Combination of galactose and fructose
Poorly absorbed and not digested by enzymes in GI tract - n&v side effects
Turns into lactic acid in colon which can have an osmotic action
Hepatic encephalopathy - helps secretion of ammonia
Laxative salts - magnesium hydroxide description
Poorly absorbed salts and osmotic action draw water into intestinal lumen
Lose dose therapy stool in 6-12 hrs
High dose used for bowel evacuation prior to surgery or to purse poisons
At risk of dehydration
Mg salts are contraindicated in patients with kidney disease
Examples of osmotic laxatives
Lactulose
Laxative salts - Magnesium hydroxide
Polyethylene glycol
Polythelene glycol description
Non absorbable compound, retain water in intestinal lumen
Causes feces to swell and soften
GI side effects (N/ bloating/ cramps/ flatulence/ diarrhea)
Can be used as a bowel cleanse prior to colonoscopy or other procedures at high doses
Example of stimulant laxative
Bisacodyl (Dulcolax)
Bisacodyl (Dulcolax) description
Stimulate intestinal motility and increases amount of water and electrolytes within bowel
Opioid induced constipation
Common drug for laxative abuse
Available as rectal suppository or PO
Given at night to produce stool the next day
Example of surfactant laxative
Docusate sodium (Colace)
Docusate sodium (Colace) description
Slow onset
Work in the small intestine and colon
Softens the stool by facilitating penetration of water
Causes secretion of water and electrolytes in intestine
Adverse effects: mild cramping, diarrhea
Nursing considerations for laxatives
Most laxatives are given until desired effect achieved and should be used short term
Laxatives can be abused
Water consumption is important
GI assessment
Most laxatives are not absorbed systemically
Description for using non specific antidiarrheals: opioids
Most effective antidiarrheal agents
Activate opioid receptors in GI to slow intestinal motility (more time for absorption of fluid and electrolytes)
May cause toxic megacolon in patients with IBD
Diphenoxylate (+Atropine) description
Brand name: Lomotil
Opioid used only for diarrhea
Atropine added to discourage abuse (unpleasant side effects)
Available PO only
Adv effects: dizziness, drowsiness, light-headedness, headache, n&v
Loperamide description
Brand name Imodium
Suppresses bowel motility and bowel secretions
Used to reduce volume of discharge from ileostomies
Large doses do not produce morphine like effects
Bismuth Subsalicylate description
Brand name: Pepto Bismol
Coats wall of GI tract
Binds to causative bacteria or toxin which is then eliminated in stool
Adv effects: increased bleeding time, constipation, dark stools, hearing loss, tinnitus, metallic taste, blue gums
Indications for ondansetron
Nausea associated with chemotherapy, radiation, anesthesia, viral gastritis and pregnancy
Ondansetron description
Trade name: Zofran
Works in CTZ
Acts on serotonin blocking receptors = less available serotonin
Often used with dexamethasone to increase effect
PO/ IV/ IM admin
Adverse effects of ondansetron
Headache, constipation, diarrhea, dizziness
Urinary retention, muscle pain
QT prolongation
Nursing considerations for ondansetron
Monitor EKG in patients at risk
Monitor for effectiveness
Indications for dexamethasone
Nausea associated with chemotherapy
Dexamethasone description
MOA unknown
Can be used with other other antiemetics (ondansetron)
Used briefly for symptom management of nausea
What kind of drug is ondansetron?
Antiemetic serotonin antagonist
What kind of drug is dexamethasone?
Antiemetic glucocorticoid
What kind of drug is metoclopramide?
Dopamine antagonist
Metoclopramide description
Trade name: Maxeran
Prokinetic drug
Blocks dopamine and serotonin receptors in CTZ, enhances upper GI tract response to acetylcholine (increase peristalsis)
Indications for metoclopramide
Nausea caused by post op, cancer medications, opioids, toxins, radiation
Adverse effects of metoclopramide
In high doses, diarrhea and sedation
With long term use: risk of tardive dyskinesia
Cl: patients with GI obstruction, perforation or hemorrhage
Tardive dyskinesia defintion
Repetitive, involuntary movements of arms, legs, and facial muscles
Nursing assessments for metoclopramide
GI assessment
Assess mental status (drowsiness)
Look for uncontrolled movement
What kind of drug is Nabilone?
Cannabinoid
Nabilone description
MOA likely activation of receptors around vomiting centre
Used to suppress chemo induced nausea and vomiting
Second line drug dye to psychotomimetic effects and potential for abuse
Nursing considerations and side effects for Nabilone
Monitor for drowsiness
SE:
CNS: temporal disintegration, dissociation (avoid in pts with psychiatric disorders)
CVS: tachycardia & hypotension (avoid in pts with cvd)
Indications for dimenhydrinate
Motion sickness, radiation, sickness, post-op, drug-induced nausea
Description for dimenhydrinate
Trade name Gravel
Blocks H1 receptors in GI tract and muscarininc receptors in vestibular system (anticholinergic)
Adverse effects of dimenhydrinate
Drowsiness, hypotension, dry mouth and constipation
Avoid with other CNS depressants
Should not be taken with hx of glaucoma or chronic lung disease, difficulty urinating
Nursing considerations for dimenhydrinate
GI assessment
Assess alertness (safety)
Vital signs (check often with CVD)
Monitor for signs of retention (bowel and bladder)
What kind of drug is scopolamine?
Muscarinic antagonist
Scopolamine description
Blocks nerve impulses between vestibular apparatus in inner ear and vomiting centre
Most effective drug for preventing and treating motion sickness
PO/ SC/ transdermal dosing
Adverse effects of scopolamine
Common: dry mouth, blurred vision, drowsiness
Less common: urinary retention, constipation, disorientation
Nursing considerations for scopolamine
GI assessment
Monitor for signs of retention (bowel & bladder)
Assess alertness (safety)
What kind of drug is sulfazalazine?
5-aminosalicylates
Sulfasalazine description
Used to treat mild or moderate IBD
Maintain remission after symptoms have improved
Action on prostaglandin synthesis and suppression of migration of inflammatory cells into affected region
Nursing considerations for sulfazalazine
Monitor CBC periodically - can cause hematological disorders
Adverse effects of sulfasalazine
Nausea, fever, rash, arthralgia
What kind of drug is budesonide?
Glucocorticoids
Budesonide description
Anti-inflammatory action
Use is to induce remission, not for long term maintenance
IV/ PO
Nursing considerations for budesonide
Prolonged use of glucocorticoids can cause severe adverse effects, adrenal suppression, osteoporosis, increased risk for infection, Cushing’s syndrome
Indications for budesonide
Mild to moderate ulcer colitis - works within the ileum and ascending colon
What kind of drug is cyclosporine?
Immunosuppressant
Cyclosporine description
Long term therapy
Calcineurin inhibitor - very strong immunosuppressant
Faster acting and stronger than other immunosuppressants
Continuous IV infusion, can be administered PO in low doses to maintain remission
Increased lymphoma risk, further increased when used with other immunosuppressants
Nursing considerations for cyclosporine
Potentially toxic compound can cause renal impairment, neurotoxicity
Generalized suppression of the immune system increases risk of infection
Indications for cyclosporine
Severe disease that has not responded to other therapies, both UC and Crohn’s
What kind of drug is Infliximab?
Immunomodulator
Infliximab description
Monoclonal antibodies
Designed to neutralize TNF, a key immunoinflammatory modulator
Infections: TB and other opportunistic infections are most common
Infusion reactions: fever, chills, pruritus, urticaria, cardiopulmonary reactions (chest pain, hypertension, hypotension)
Increased risk of lymphoma
6 wk regimen followed by maintenance infusions Q8Wks
Indications for Infliximab
Moderate to severe UC and Crohn’s
