Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > GI Pharmacology > Flashcards

GI Pharmacology Flashcards

1
Q

What are the different GI disorders?

A

Gastroesophageal Reflux Disease (GERD)

Peptic Ulcer Disease (PUD)

Duodenal Ulcer

Nausea

Emesis

IBS

Diarrhea

Constipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Gastric Mucosal Barrier

A
  • The alkaline-rich mucus produced by mucosa cells in the pyloric region that protects the epithelium of the stomach and duodenum from harsh acid conditions of the lumen
  • These cells are stimulated by mechanical and chemical irritation and parasympathetic inputs.
  • This protective mucus barrier can be damaged by bacterial and viral infection, certain drugs, and aspirin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

GERD

A
  • Backflow of stomach acid into the esophagus, which can cause scarring
  • Usual symptom of heartburn (burning sensation behind the breastbone; MI is often mistaken for GERD)
  • severe symptoms=difficulty swallowing and chest pain
  • complications include esophageal erosions, esophageal ulcer and esophageal stricture (narrowing)
  • ~10% pts, normal esophageal lining is replaced with Barrett’s epithelium (aka Barrett’s esophagus) and has been linked to cancer
  • Precipitants include: fatty food, alcohol, caffiene, smoking, obesity, and pregnancy

—this is usually a chronic/relapsing course

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Peptic Ulcer Disease

A
  • Can be benign or malignant
  • Benign: normal gastric acid production, but the mucosal barrier is weak
  • Malignant: Excessive secretion of gastric acid that overwhelms the mucosal barrier
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Treatments for GERD and PUD

A
  • Antacids
  • H2 Receptor Blockers
  • Mucosal Protective Agents
  • Proton Pump Inhibitors
  • Anti-cholinergics
  • Prostaglandin Analogs
  • Anti-microbial Agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Antacids

A

Systemic antacid: Sodium bicarbonate

Nonsystemic antacids: Aluminum Hydroxide+Mg Hydroxide (Maalox and Mylanta)

  • Maalox and Mylanta are contraindicated in pts with impaired renal function and Mg may cause diarrhea
  • Calcium carbonate (Tums): Ca may cause constipation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

H2 Receptor Blockers

A
  • Cimetidine
  • Famotidine
  • Ranitidine
  • Nizatidine
  • Inhibit secretion of gastric acid through competitive inhibition of Histamine H2 receptors
  • Prevention and Tx of PUD, Esophagitis, GI bleeding, stress ulcers, and Zollinger-Ellison Syndrome
  • May alter the effects of other drugs through interactions with CYP450 (especially cimetidine)
  • Very few side effects (except for cimetidine which inhibits metabolism of estrogen which can cause breast tissue growth in men when taken long term)
  • Suppresses 24 hour gastric secretion by 70%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Proton Pump Inhibitors (PPIs)

A
  • Omeprazole
  • Esomeprazole
  • Rebeprazole
  • Lansoprazole
  • Pantoprazole
  • Strong inhibitors of gastric acid secretion through irreversible inhibition of proton pump
  • Prevents release or pumping of gastric acid (24 hr action)
  • Indicated in PUD, Gastritis, GERD, & Zollinger-Ellison syndrome
  • Faster relief and healing than H2 receptor blockers
  • Decreases acid secretion by up to 95% for up to 48 hours -4-8 week course of treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mucosal protecting agents

A

Sucralfate (carafate)

  • -used to prevent and Tx PUD
  • -requires an acidic pH to activate
  • -forms a sticky polymer in the acidic environment & adheres to the ulcer site forming a barrier

Chelated Bismuth

  • -protects the ulcer crater and allows healing -some activity against H. pylori
  • -should not be used repeatedly or for more than 2 months at a time
  • -can cause black stools and constipation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Anti-H. pylori therapy

A

>85% PUD caused by H. pylori Antibiotic Ulcer Therapy: Used in Combinations

  • Bismuth: Disrupts bacterial cell wall
  • Clarithromycin: Inhibits protein synthesis
  • Amoxicillin: Disrupts cell wall
  • Tetracycline: Inhibits protein synthesis
  • Metronidazone: Used often due to bacterial resistance to amoxicillin and tetracycline, or due to intolerance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Anti-H. pylori therapy

A

Triple Therapy is a 7 day treatment 80-85% effective

-Proton pump inhibitor + amoxicillin/tetracycline + metronidazone/clarithomycin

Quadruple Therapy is a 3 day treatment and as efficacious as triple therapy

-Add Bismuth to triple therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Prostaglandins

A

Misoprostol

  • PGE1 analog
  • Stimulates GI pathway leading to a decrease in gastric acid release
  • For treatment of NSAID induced injury
  • Side effects include diarrhea, pain, and cramps (30%)

**Do not give to women of childbearing years unless a reliable method of birth control can be DOCUMENTED

**Can cause birth defects, and premature birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Anticholinergics

A

Pirenzipine

  • Muscarinic M1 Ach receptor antagonist
  • Blocks gastric acid secretions
  • About as effective as H2 blockers
  • Rarely used, primarily as adjunct therapy
  • Anticholinergic side effects (anorexia, blurry vision, constipation, dry mouth, sedation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Inflammatory Bowel Disease

A

Ulcerative Colitis

  • A diffuse mucosal inflammation limited to the colon
  • Bloody diarrhea, colicky pain, urgency, tenesmus (feel like you have to use the bathroom even though bowels are empty) Crohn’s Disease
  • Patchy transmural inflammation
  • May affect any part of the GI tract
  • Causes abdominal pain, diarrhea, weight loss, intestinal obstruction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Treatment for Inflammatory Bowel Disease

A

Goal of treatment is to resolve the acute episodes and prolong remission

  • Aminosalicylates - for mild symptoms
  • Corticosteroids - for moderate symptoms
  • Thiopurines - for active and chronic symptoms
  • Methotrexate - for active and chronic symptoms
  • Cyclosporin - for active and chronic symptoms refractory to corticorsteroids- (significant side effects)
  • Infliximab - antibody infusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Constipation

A
  • Usually effectively treated with dietary modification
  • Only if this fails should laxatives be used
  • Laxative abuse is #1 cause of constipation

Therapy:

  • -Bulking agents
  • -Osmotic laxatives
  • -Stimulant drugs
  • -Stool softeners
17
Q

Bulk laxatives

A
  • Increase in bowel content volume triggers stretch receptors in the intestinal wall
  • Causes reflex contraction (peristalsis) that propels the stool forward

Psyillium

Bran

Methylcellulose

  • -insoluble and non-absorbable
  • -non digestible
  • -must be taken with lots of water or it will make constipation worse
18
Q

Saline and Osmotic Laxatives

A
  • Effective in 1-3hrs
  • used to purge the intestine (i.e. surgery or poisoning)
  • Fluid is drawn into the bowel by osmotic force, increasing volume and triggering peristalsis
19
Q

Saline and Osmotic Laxatives

A

Nondigestible sugars and alcohols:

  • -Lactulose (broken down by bacteria to acetic and lactic acid, which causes the osmotic effect)

Salts:

  • -Milk of Magnesia (Mg(OH)2)
  • -Epsom Salt (MgSO4)
  • -Glauber’s Salt (Na2SO4)
  • -Sodium Phosphates (used as enema)
  • -Sodium Citrate (used as enema) Polyethylene glycol
20
Q

Stool Softeners-Emollients

A

Docusate sodium (surfactant and stimulant)

Liquid parafin (oral solution)

Glycerin suppositories

21
Q

Irritant/Stimulant Laxatives

A
  • Increase intestinal motility
  • Irritate the GI mucosa and pull water into the lumen
  • Indicated for severe constipation where more rapid effect is required (6-8hrs)

Therapy:

  • Castor oil-from the castor bean
  • Senna-plant derivative
  • Bisacodyl
  • Lubiprostone-PGE1 derivative that stimulates chloride channels and produces Cl rich secretions
22
Q

Laxative Abuse

A
  • Most common form of constipation
  • A longer interval is needed to refill colon after use and is misinterpreted as constipation=repeated use
  • Enteral loss of water and salts causes release of aldosterone
  • This stimulates reabsorp. in the intestine and increases renal excretion of K
  • Double loss of K=hypokalemia which reduces peristalsis & is misinterpreted as constipation which leads to repeated laxative use
23
Q

Diarrhea

A
  • Caused by Toxins
  • Caused by microorganisms: Shigella, salmonella, E.coli, campylobacter, c.diff
  • Caused by antibiotic associated colitis

Indications for treatment

  • -Last longer than 2-3 days
  • -severe diarrhea in elderly or small children
  • -chronic inflammatory disease
  • -when a specific cause has been determined
24
Q

Anti-Diarrheal Agents

A

Anti-motility Agents Reduce peristalsis by stimulating opioid receptors in the bowel

Allow time for more water to be absorbed by the gut

  • Morphine
  • Codeine
  • Diphenoxylate
  • Loperamide:
  • -40-50x more potent than morphine
  • -Poor CNS penetration
  • -Increases transit time and sphincter tone
  • -Antisecretory against cholera & some E.coli toxin
  • -T½ 11 hours, dose: 4 mg followed by 2mg doses (16mg/d max)
  • -Overdose: paralytic ileus, CNS depression
  • -Caution in IBD (toxic megacolon)

Contraindications for antidiarrheals

  • -Toxic Materials
  • -Microorganisms (salmonella, E.coli)
  • -Antibiotic associated
25
Q

Clostridium difficile

A

The major cause of diarrhea and colitis in patients exposed to antibiotics

Fecal - oral route of transmission

Three steps to infection:

  • -Alteration of normal fecal flora
  • -Colonic colonization of C. difficile
  • -Growth and production of toxins Infection can lead to formation of colitis and toxic megacolon

Pharmacological Treatment:

  • -Discontinue offending antibiotic
  • -Metronidazole (contraindicated in patients with liver or renal impairment)
  • -Vancomycin (contraindicated in patients with renal impairment)
26
Q

Antiflatulants

A

-Used to relieve the painful symptoms associated with gas

Simethicone (a detergent):

  • Alters elasticity of mucus-coated bubbles, causing them to break
  • Large bubbles -> smaller bubbles, and less pain -Used often, but limited data regarding effectiveness
27
Q

Emesis

A

Occurs via activation of three main areas in the brain

  • -Cortex (see something repulsive)
  • -Vestibular apparatus (motion sickness)
  • -Chemoreceptor Trigger Zone (feeds into the vomiting center in the brain)

Ingesting a toxin also causes emesis

28
Q

Syrup of Ipecac Emetic

A
  • Prepared from the root of the ipecacuanha plant
  • Induces emesis
  • Side effects include drowsiness, diarrhea, and stomach ache

Acceptable for use when:

  • -There is no contraindication to the use of ipecac
  • -There is risk of serious toxicity to the victim
  • -No alternative therapy is available or effective to decrease gastrointestinal absorption (e.g., activated charcoal)
  • -There will be a delay of greater than 1 hour before the patient will arrive at an emergency medical facility and ipecac syrup can be administered within 30-90 minutes of the ingestion
  • -Ipecac syrup administration will not adversely affect more definitive treatment that might be provided at a hospital
29
Q

Antiemetic Therapeutics M1 receptor antagonist

A

Muscarinic (M1) receptor antagonist

-Scopolamine (skin behind the ear is best place for patch b/c skin is thinnest there)

Side Effects:

  • -dry mouth
  • -dizziness
  • -restlessness
  • -dilated pupils
  • -delirium at high doses
  • -allergic reaction

Contraindications:

  • -kidney or liver disease
  • -enlarged prostate
  • -difficulty in urination/bladder problems
  • -heart disease -glaucoma
30
Q

Antiemetic Therapeutics Histamine H1/Dopamine D2 receptor antagonist

A

Phenothiazines

Promethazine (Phenergan)

Prochlorperazine (Compazine)

Side Effects:

  • -These drugs are neuroleptics (typical antipsychotics)
  • -Blurred vision
  • -Dry mouth
  • -Dizziness
  • -Restlessness
  • -Seizures
  • -Extrapyramidal effects - Tardive dyskinesia (long term treatment)

Contraindications:

  • -Allergy to phenthiazines
  • -Glaucoma
  • -Liver disease
  • -Prostate / bladder problems
31
Q

Antiemetic Therapeutics Serotonin 5-HT3 receptor antagonist

A

Excellent for chemotherapy induced nausea and vomiting

  • Ondansetron (Zofran)
  • Granisetron

Side Effects:

  • -Very few common side effects
    • usually well tolerated
  • -Headache
  • -Constipation

Rarely:

  • -Hiccups
  • -Itchiness
  • -Transient blindness

Pharmacology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions