GI Drugs Flashcards
H2 blockers
end in "-tidine" Cimetidine Ranitidine Famotidine Nizatidine
H2 blockers: Mechanism
Reversible block of histamine (H2-receptors) – leads to decrease in H+ secretion by parietal cells
H2 blockers: Clinical Use
Peptic Ulcer, Gastritis, mild esophageal reflux
H2 blocker Toxicity:
Cimitidine has a lot of side effects
- Potent inhibitor of P-450 (higher concentrations of other drugs)
- Has anti-androgenic effects (prolactin release, gynecomastia, impotence, decrease libido in males)
- Can cross blood-brain barrier (confusion, dizziness, headaches) and placenta
- Both cimitidine and ranitidine decrease renal excretion
Proton Pump Inhibitors
Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlansoprazole
Proton Pump Inhibitors (“-prazole”): Mechanism
Irreversibly inhibit H/K/ATPase in stomach parietal cells
Proton Pump Inhibitors (“-prazole”: Clinical Use
Peptic ulcer, Gastritis, Esophageal Reflux, Zollinger- Ellison syndrome
Proton Pump Inhibitors (“-prazole”): Toxicity
Increased risk of C. difficile infection, pneumonia. Hip fractures,
- Decreased serum Mg with long term use
Bismuth, Sucralfate: Mechanism
Bind to ulcer base, providing physical protection and allowing HCO3 secretion to re-establish pH gradient in mucous layer
Bismuth, Sucralfate: Clinical Use
Increase ulcer healing, traveler’s diarrhea
Misoprotol: Mechanism
A PGE-1 analog. Increase production and secretion of gastric mucous barrier. Decrease acid production
Misoprotol: Clinical Use
Prevention of NSAID induced peptic ulcer; maintenance of PDA.
- Also used to induce labor (ripens cervix)
Misoprotol: Toxicity
Diarrhea. Contraindicated in women of childbearing potential (abortificatin)
Octeotride: Mechanism
Long-acting somatostatin analog
Octeotride: Clinical Use
Acute variceal bleeds, acromegaly, VIPoma and carcinoid tumors
Octeotride: Toxicity
Nausea, cramps, steatorrhea
Antacid Use
- Can affect absorption, bioavailability or urinary excretion of other drug by altering urinary pH or delaying gastric emptying
- All can cause HYPO-kalemia
Aluminum hydroxide
Antacid
- Can cause constipation and HYPOphosphatemia; proximal muscle weakness, osteodystrophy, seizures
**AluMINIMUM amount of feces”
Magnesium hydroxide
Antacid
- can cause diarrhea, HYPOreflexia, HYPOtension, Cardiac arrest
“Think Milk of Magnesia (laxative)
** Mg = Must Go to the bathroom
Calcium carbonate
Hypercalcemia, Rebound acid increase
Osmotic laxatives
Magnesium Hydroxide, Magnesium Citrate, Polyethylene glycol, Lactulose
Oxsmotic laxatives: Mechanism
Provide osmotic load to draw water out
Discuss lactulose and hepatic encephalopathy
Lactulose treats hepatic encephalopathy since gut flora degrades it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4
Osmotic laxative: Clinical Use
Constipation
Osmotic laxative: Toxicity
Diarrhea, dehydration, may be abused by bulimics
Infliximab: Mechanism
Monoclonal antibody to TNF-alpha
Infliximab: Clinical Use
Crohn’s disease, UC, Rheumatoid arthritis
Infliximab: Toxicity
Infection (including reactivation of latent TB), fever, hypotension
Sulfasalazine: Mechanism
A combination of sulfapyridine (anti-bacterial) and 5-aminosalicylic acid (anti-inflammatory)
- Activated by colonic bacteria
Sulfasalazine: Clinical USe
UC, Crohn’s disease
Ondanestron: Mechanism
5-HT3 antagonist. Powerful central-acting anti-emetic.
Ondansetron: Clinical Use
Control vomiting postoperatively and in patients undergoing cancer chemotherapy
Ondansetron: Toxicity
Headache, constipation
Sulfasalazine: Toxicity
Malaise, nausea, sulfonamide toxicity, reversible oligospermia
Metoclopramide
D2 receptor antagonist
- Increase resting tone, contractility, LES tone, motility
- Does not influence colon transport time
Metoclopramide: Clinical USe
Diabetic and post-surgery gastroparesis, anti-emetic
Metoclopramide: Toxicity
Increase in parkinosonian effects
- Restlessness, drowsiness, fatigue, depression, nausea, diarrhea
- Drug interaction with digoxin and diabetic agents
- Contraindicated in patient with small bowel obstruction or Parkinson’s disease
