GI pharm Flashcards
What are the H2 blockers?
Cimetidine, ramitidine, famotidine, nizatidine
H2 blockers mech
Reversible block of histamine H2 receptors which decreases H+ secretion by parietal cells
Clinical use of H2 blockers
Peptic ulcer, gastritis, mild esophageal reflux
What is the H2 blocker with the most SE/Toxicity, and what are the SE?
Cimetidine is a potent inhibitor of CYP-450 (multiple drug interactions); it also has antiandrogenic effects (prolactin release, gynecomastia, impotence, decreased libido in males); can cross blood-brain barrier (condusion, dizziness, headaches) and placenta. Both cimetidine and ranitidine decrease renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
What are the PPI’s?
Omeprazole, Lansoprazole, esomeprazole, pantoprazole, dexlansoprazole.
What is the mech of PPI?
Irreversibly inhibit H+/K+ ATPase in stomach parietal cells
What is the clinical use of PPIs?
peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
Toxicity of PPIs?
Increased risk of C. Diff infection, pneumonia. Hip fractures, decreased serum Mg+2 with long-term use
What is the mech of Bismuth, Sucralfate
Bind to ulcer base, providing physical protection and allowing HCO3- secretion to reestablish pH gradient in the mucous layer
What is the clinical use opf Bismuth, Sucralfate
Increase ulcer healing, travelers’ diarrhea
Misoprostol mech
A PGE1 analog. Increased production and secretion of gastric mucous barrier, decreases acid production
What is the clinical use of Misoprostol?
Prevention of NSAID induced peptic ulcers (NSAIDs block PGE1 production); maintenance of a PDA. Also used to induce labor (ripens cervix)
Octreotide mech
Long-acting somatostatin analog.
Clinical use of Ostreotide?
Acute variceal bleeds, acromegaly, VIPoma, and carcinoid tumors.
Toxicity of Octreotide?
Nausea, cramps, steatorrhea
What are the Antacids?
Aluminum Hydroxide, Calcium Carbonate, Magnesium Hydroxide.
What are the Antacids used for?
Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying. All can cause hypokalemia. Overuse can also cause the following problems
Aluminum Hydroxide SE?
Constipation and hypophosphatemia; proximal muscle weakness, osteodystrophy, seizures. aluMINIMUM amount of feces
Calcium Carbonate SE?
Hypercalcemia, rebound acid increase! Can chelate and decrease effectiveness of other drugs (i.e. tetracycline)
Magnesium Hydroxide SE?
Diarrhea, hyporeflexia, hypotension, cardiac arrest. Mg=Must Go to the bathroom
What are the Osmotic laxatives?
Magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose.
What is the mech of Osmotic Laxatives?
Provide osmotic load to draw water out. Lactulose also treats hepatic encephalopathy since gut flora degrade it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4+
What is the clinical use of Osmotic Laxatives?
Constipation
What is the toxicity of Osmotic Laxatives?
Diarrhea, dehydration; may be abused by bulimics
What is the mech of Infliximab?
monoclonal antibody to TNF-alpha
Clinical use of Infliximab?
Crohn disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriasis
Toxicity/SE of Infliximab?
Infection (including reactivation of latent TB), fever, hypotension
Sulfasalazine mech
A combination of sulfapyridine (antibacterial) and 5-aminosalicyclic acid (anti-inflammatory). Activated by colonic bacteria.
What is the clinical use of Sulfasalazine?
Ulcerative Colitis, Crohn disease.
What is the SE/Toxicity of Sulfasalazine
Mailaise, nausea, sulfonamide toxicity, reversible oligospermia.
Mech of Ondansetron
5-HT3 antagonist; decreased vagal stimulation. Powerful central-acting antiemetic.
Clinical use of Ondansetron
Control vomiting postoperatively and in patients undergoing cancer chemotherapy.
SE/Toxicity of Ondansetron
Headache, constipation
Metoclopramide mech?
D2 receptor antagonist. increase resting tone, contractility, LES tone, motility. Does not influence colon transport time.
Clinical use of Metoclopramide?
Diabetic and post surgery gastroparesis, antiemetic
Toxicity/SE of Metoclopramide?
Increased parkinsonian effects. Restlessness, drowsiness, fatigue, depression, nausea, diarrhea. Drug interction with digoxin and diabetic agents. Contraindicated in patients with small bowel obstruction or Parkinson disease (D1 receptor blockade)
