GI Drugs (Exam #2) Flashcards
What are the two antacids, and what is the major AE of each?
- Magnesium hydroxide = diarrhea
- Aluminum hydroxide = constipation
What are the two primary H2 Histamine Antagonist drugs? What is the name hint?
“-tidine”
- Cimetidine (Tagamet)
- Ranitidine (Zantac)
What are the two primary PPIs? What is the name hint?
“-prazole”
- Omeprazole (Prilosec)
- Esomeprazole (Nexium)
What is the MOA of Misoprostol, and what is its primary use?
PGE1 analogue
- Used to prevent NSAID-induced ulcers
What is the one CI associated with Misoprostol, and why?
PREGNANCY
- Can induce uterine contractions/abortion bc PG analogue
What is an important note with antacids and drug interactions?
Antacids DECREASE absorption of other drugs
What two GI drugs are NOT recommended in those with renal dysfunction, and why?
Magnesium and Aluminum (mostly long-term use)
- Excreted by kidneys so if poor renal function → toxicity
What is an important AE of Cimetidine? What is an alternative use of this medication?
Anti-androgen effect
- Can be used to treat masculinization in females
How does Cimetidine differ from other H2 Antagonists (think AEs)?
Drug interactions (inhibits CYP3A4) - Avoid with Warfarin, Phenytoin, Theophylline
What is the DOC for GERD? What is the MOA of these drugs?
PPIs
- IRREVERSIBLY inhibit proton pump
Chronic use of PPIs can lead to what three AEs?
Decreased absorption of…
- Ca = osteoporosis
- Mg = hypomagnesemia/muscle spasms
- B12 = Vitamin B12 deficiency
Which PPI is associated with drug interactions, and what are four examples of this?
Omeprazole = inhibits CYP2C19
- Phenytoin
- Diazepam
- Warfarin
- Clopidogrel
What four abx can be used to treat H. pylori-induced ulcers?
- Metronidazole (Flagyl)
- Amoxicillin
- Tetracycline
- Clarithromycin
What group of drugs are used to stimulate GI activity, and what are three examples?
Prokinetic Agents
- Metoclopramide (Reglan)
- Bethanechol
- Erythromycin
What is the MOA of Metoclopramide (Reglan), and what AE is associated with this?
D2 receptor antagonist
- EPS (Parkinson-like sxs) - especially old/hospitalized
What is the MOA of Bethanechol?
Muscarinic agonist
What group of drugs are used to inhibit GI activity, and what are two examples? What condition are they used to treat?
Antispasmodics for IBS
- Dicyclomine (Bentyl)
- Amitriptyline
What GI condition can Amitriptyline be used to treat? What symptom can it also relieve, and how?
IBS (antispasmodic)
- Reduce chronic pain via increased NE → stimulate alpha2 receptors
What group of drugs is primarily used to treat nausea/vomiting? What two types of N/V specifically (and which type are they NOT good for)?
What is the name hint of these drugs?
5HT3 Receptor Antagonists = “-setron”
- Good for N/V due to chemo or vagal stimulation
- NOT good for N/V due to motion sickness
Which two drugs are used to treat N/V by blocking D2 DA receptors, muscarinic receptors and H1 histamine receptors?
- Prochlorperazine (Compazine)
- Promethazine (Phenergan)
What is the main AE associated with Prochlorperazine (Compazine) and Promethazine (Phenergan), and why?
Sedation
- Due to blockade of muscarinic receptors and H1 histamine receptors
What drug is a form of THC used to treat chemo-induced N/V?
Dronabinol
What drug must ALWAYS be combined with a 5HT3 Antagonist and corticosteroid? What is the primary use of this drug?
Aprepitant
- Used for severe chemo-induced N/V
Under what three circumstances are laxatives NOT recommended for use?
- Intestinal blockage
- Perforation
- Toxic megacolon
What is the MOA of Aprepitant?
NK1 Antagonist (all “-pitant” drugs)
What group of drugs is Lactulose, and what is an important alternative use?
Osmotic Laxative (tx constipation) - Decreases ammonium buildup in cirrhosis patients
What drug is often used as preparation for colonoscopies? What is an alternative use?
Polyethylene Glycol
- Can be used as OTC treatment for occasional constipation (Miralax)
What is the recommended time of use for osmotic laxatives, and why? What is the exception?
ONLY acute constipation (not chronic because leads to electrolyte imbalances)
- Lactulose can decrease ammonium buildup in cirrhosis
What medication treats constipation by acting on the mucosa?
Senna (Senokot)
What two meds can be used to tx constipation CHRONICALLY?
- Lubiprostone
- Linactolide
What is the MOA of Lubiprostone, and what is its primary use?
PGE1 derivative
- Used to tx CHRONIC constipation
What is the MOA of Linactolide, and what is its primary use?
cGMP stimulates CFTR → increase Cl secretion
- Used to tx CHRONIC constipation
What is the MOA of Naloxegol (Movantik), and what is its primary use?
Opioid Antagonist
- Used to tx opioid-induced constipation
What type of drug is Loperamide (Imodium), and what are two important PK for this drug?
Antidiarrheal
- NO CNS effect = low abuse potential
- OTC
What drug is Diphenoxylate often combined with, and why?
Diphenoxylate has CNS effects = HIGH abuse potential
- Add Atropine to decrease this (also decreases spasms)
What drug is an Anti-Inflammatory used to treat IBD?
Sulfasalazine
What are two CIs associated with Bismuth Subsalicylate (Pepto Bismol)?
- Allergy to ASA
- Children (Reye’s Syndrome)
What drug can be used to treat flatulence?
Simethicone (Gas X)
