GI Drugs Flashcards
Calcium Carbonate
Antacid
⁃ High ANC
⁃ Rapid Onset / Long Acting
⁃ Releases CO2
⁃ AE:
⁃ Hypercalcemia
⁃ Nephrolithiasis
⁃ Milk-Alkali Syndrome
Sodium Bicarbonate
Antacid
⁃ High ANC
⁃ Rapid Onset/ Short Acting
⁃ Releases CO2
⁃ AE:
⁃ Systemic Alkalosis
⁃ Fluid Retention
Aluminum Hydroxide
Antacid
⁃ Low ANC
⁃ Slow onset/ Long acting
⁃ Binds Pepsin
⁃ AE:
⁃ Constipation
⁃ Hypophosphatemia
⁃ Decreases Bioavailability of other drugs due to binding
Note: Mix with Milk of Magnesia to balance the constipation AE.
Magnesium Hydroxide
Antacid
⁃ High ANC
⁃ Rapid Onset/ Long Acting
⁃ AE:
⁃ Diarrhea
⁃ Hypermagnesemia in Renal patients
Bismuth Subsalicylate
Cytoprotective
⁃ Cytoprotection mechanism unknown
⁃ Antisecretory
⁃ Anti-inflammatory
⁃ Antimicrobial
⁃ AE:
⁃ Black Stool
⁃ Neurological Injury via Bismuth absorption
Cimetidine
H2 Receptor Antagonist
RX:
- PUD
- GERD
- ZE
- Erosive Esophagitis
AE:
Gynacomastia
Impotence
Inhibits:
- CYP1A2, 2C9, 2D6, 3A4
Ranitidine
H2 Antagonist
Famotidine
H2 Antagonist
No CYP interaction; Longest Half life; high bioavailability
Omeprazole
PPI
Rx:
- GERD
- Erosive Esophagitis
- PUD (Hpylori, NSAIDS induced)
- Dyspepsia
- Prevention of Stress Ulcers in ICU (IV use)
- ZE
MOA:
- Inhibits HKATPase of PArietal Cell Irreversibly
- Prodrug
AE:
- Hepatic Liver Induction (Clopidogrel, Warfarin, Methotrexate, Tacrolimus)
- CDIFF infection risk
- Osteoporosis
- Hypomagnesemia
- B12 Deficiency
Esomeprazole
PPI
IV and PO
Less AE than Omeprazole
Lansoprazole
PPI
PO and IV
OTC
Misoprostol
Cytoprotective
Rx:
- Prevent NSAID induced Ulcers
- Available in combination with NSAIDS
MOA:
- Increase Mucus and bicarb secretion from superficial epithelial cells
- Decrease Acid secretion
- Maintain Submucosal Flow
AE:
- Diarrhea
- Colic
- CONTRAINDICATED in Pregnancy
Sucralfate
Cytoprotective
Rx:
- Ulcer Healing
- (Can be given with NSAIDS)
Note: Rarely used
MOA:
- Forms Viscous gel in Acid
- Binds to inflamed tissue
- Protects ulcer from acid
- Inhibits absorption of other drugs
AE:
- Constipation
Bismuth Subsalicylate
Cytoprotective
MOA:
- Unknown mechanism
- Anti-secretory
- Anti-inflammatory
- Anti-microbial
- Anti-diarrheal
AE:
- Neurological Injury due to Bismuth absorption
- Black Stool
Propantheline
Antimuscarinic
Quaternary Amine
Rx:
⁃ PUD
⁃ Hypermotility
Dicyclomine
Antimuscarinic
Tertiary Amine
Rx:
⁃ peptic disease
⁃ Hypermotility
Amitriptyline
Antidiarrheal
Anticholinergic/ Antispasmotic
Rx:
IBD
Glycopyrrolate
Quaternary Antimuscarinic
Rx:
Treat Ulcers
Hyoscyamine
Antimuscarinic
Rx:
Gastric Spasms
Ulcers
*Not used much anymore; used to be used to increase LES.
Cisapride
Prokinetic
⁃ 5HT4 agonist
⁃ Was widely used in GERd to contract LES.
⁃ Available for Compassionate use only
⁃ can be found on internet though
⁃ AE:
⁃ Cardiac arrhythmia
⁃ Long QT
Metoclopramide
Prokinetic
MOA:⁃
-5HT4 agonist
⁃ 5HT3 antagonist (CNS and Vagus)
⁃ D2 antagonist
⁃ Enhances actions of ACh
RX:
GERD
Increase LES
Gastroparesis
Antiemetic in cancer Rx
AE:
⁃ Extrapyramidal effects from D2 antagonism.
⁃ Parkinson like- short term, reversible.
⁃ Long term use results in irreversible Tardive dyskinesia
⁃ Galactorrhea
Contra:
GI obstruction
Bleeding/ Perforation
Erythromycin
Prokinetic
⁃ Motilin like activity
⁃ Short term use for Gastroparesis Rx
⁃ Tolerance develops
Domperidone
Prokinetic
D2 receptor antagonist
Fewer CNS and CV side effects
Available through Investigator IND and in Canada
Bethanechol
Prokinetic
Muscarinic Agonist
Not hydrolyzed by acetylcholinesterase and therefore long half life
⁃ formerly used for GERD Rx
⁃ Widespread cholinergic AEs
Neostigmine
Prokinetic
AChE inhibitor
Stimulates nicotinic and muscarinic receptors
No CNS effects
Rx:
⁃ formerly used for GERD Rx
⁃ Widespread cholinergic AEs
Alosetron
Antidiarrheal
MOA:
⁃ Selective 5HT3 Antagonist
⁃ Reduces lower abdominal pain and discomfort, cramps, urgency, diarrhea
⁃ Use:
⁃ Severe diarrhea dominant IBS in women who have not responded to other therapy.
⁃ AE:
⁃ Constipation
⁃ Can be severe
⁃ Ischemic colitis (can be fatal)
Loperamide
Antidiarrheal
Opioid
MOA:
Acts on mu opioid receptor
Slows down the GI for more H2O absorption.
Rx:
IBD Diarrhea
Bismuth Subsalicylate
Cytoprotective
MOA:
Unknown mechanism
Anti-secretory
Anti-inflammatory
Anti-microbial
Anti-diarrheal
AE:
Neurological Injury due to Bismuth absorption
Black Stool
Psyllium
Laxatives
Mild Stool softener
Dietary Fiber
Magnesium Hydroxide
Laxative (and antacid)
Intense
MOA:
Mg++ draws fluid into the intestine via osmosis
Mg++ stimulates the release of CCK which results in increased water, electrolytes, and motility in the lumen.
AE:
Hypermagnesemia
Polyethylene Glycol
Laxative
Intense
Osmotic laxative
Use:
Bowel Prep before Surgery
Bisacodyl
Laxative
Moderate
Stimulates the CNS to increase NaCl and Fluid secretion; colonic stimulation mainly
Lubiprostone
Rx:
Chronic constipation of unknown cause and IBS
MOA:
Acts on GI epithelial chloride channels to release Cl- and subsequently stimulate fluid secretion to soften the stool
Linaclotide
Prokinetic
MOA:
Guanylate cyclase agonist, increases cGMP
Stimulates chloride and bicarb secretion via activation of Cystic fibrosis regulator channel.
Increases GI transit time and reduces abdominal pain- 1x daily before 1st meal
Rx:
IBS with constipation or idiopathic constipation
AE:
Diarrhea with pain (Can be life threatening)
GERD
Sodium Phosphate
Laxative
Fast
Rx:
Not really used; used to be used for colonoscopy prep.
AE:
Phosphate nephropathy in renal patients
Tegaserod
Prokinetic
MOA:
⁃ 5HT4 partial agonist
⁃ Approved for emergency use for severe constipation in IBS.
⁃ Available from FDA only for emergencies
⁃ AE:
⁃ Withdrawn from market
⁃ Serious Cardiac AEs
Sulfasalazine
IBD Drug (First Line Rx for UC)
Inflammatory Mediator modulation via LOC pathway
Prodrug converted to 5ASA
MOA:
Inhibits Nf-kappaB and inhibits formation of inflammatory cytokines
Inhibits NK cells
Mesalamine
5-ASA (Active form of Sulfasalazine)
Thus, sulfasalazine metabolite
Budesonide
Glucocorticoid
Rectal suppository available if there is rectal or sigmoid disease
Large 1st pass effect
RX:
IBD
Hydrocortisone
Rx:
IBD
Adalimumab
IgG antibody
Anti-TNF
SubQ
Rx:
Crohn’s Disease
Infliximab
IgG
IV
Crohn’s disease
Azathioprine
Immunomodulator
Prodrug of 6 Mercaptopurine
Rx: IBD
MOA:
Purine analogue- inhibits nucleotide synthesis
⁃ Azathioprine and 6MP
⁃ Used to induce and maintain remission in UC and Crohn’s.
⁃ PO or IV daily for 6mos
⁃ AE:
⁃ Nausea
⁃ Vomiting
⁃ Bone Marrow depression
⁃ Hepatotoxicity
Methotrexate
⁃ Inhibition of dihydrofolate reductase
⁃ Low dose, once weekly for 8-12 weeks
Rx:
Crohn’s disease
MOA:
Blocks purine synthesis
⁃ AE:
⁃ Uncommon at low doses
⁃ Bone marrow suppression
⁃ Anemia
⁃ Alopecia
⁃ Mucositis
⁃ Reno-hepatic toxicity potential
Note: Do not use with PPI
Cholestyramine
Bile salt binder
Lowers Cholesterol
Used to prevent diarrhea in Cronh’s disease
AE:
gallstone formation
N-Acetylcysteine
Acetaminophen antidote
MOA:
Binds to NAPQI via the donation of a sulfhydril group
Ursodiol
Reduces the rate of cholesterol absorption by the GI
Breaks down Micelles containing cholesterol
Pancrelipase
synthetic mixture of pancreatic enzymes:
Lipase
Amylase
Chymotrypsin
Cimetidine
H2 Receptor Antagonist
RX:
- PUD
- GERD
- ZE
- Erosive Esophagitis
AE:
- Hepatic Enzyme Inhibition
- Antiandrogenic
- Gynecomastia (inhibits estradiol metabolism)
- Caution in renal pts
