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48 Cards in this Set
- Front
- Back
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H2 Receptor Antagonists
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Competitive inhibitors of Histamine H2 Receptors
Good oral absorption Reach peak serum conc. in 1-3 hr In CSF, crosses placenta, in breast milk |
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Cimetidine
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First blocker of gastric acid secretion
Works in minutes Limited side effects because H2 mainly in stomach and doesnt readily cross BBB Inhibits CytP450 and slows down metabolism of other drugs Inhibits androgen receptors and increases prolactin Caution in patients with liver/CV disease |
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Ranitidine
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Longer lasting and 10X more potent than Cimetidine
Less CytP450 activity so fewer drug interactions No androgen/prolactin effects Caution in patients with liver/renal insufficiency |
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Famotidine
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30x more acive than cimetidine: most potent H2 Antagonist
Negligible CytP450 effects No effect on prolactin Given to surgery patients preop |
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Nizantidine
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Just like ranitidine but little hepatic metabolism so 100% oral avail.
Side effects are anemia and hives |
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Proton Pump Inhibitors
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Irreversibly binds H/K ATPase of gastric parietal cell
99% reduction in gastric acid secretion Only affect active pumps (25% of pumps are new daily) Given in inactive form and absorbed in SI where it travels through blood to canaliculi base Encapsulated to avoid acid in stomach |
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Omeprazole
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Racemate (S and R)
R undergoes chiral shift to S in vivo CYP 219 facilitates chiral shift so potential for "poor metabolizer effect" |
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Esomeprazole
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S Enantiomer only
No "poor metabolizer effect" |
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Pros for Omeprazole/Esomeprazole
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Highly selective, effective, long lasting
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Cons for Omeprazole/Esomeprazole
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Not for immediate relief
Do not crush tablets- enteric coating needing |
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PPI side effects
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Risk of fracture with longterm use
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Ulcer Treatment
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Clarithromycin Triple Therapy:
PPI+ Clarithromycin+ Amox/Metronidazole Bismuth Quad. Therapy: PPI/H2RA+ Bismuth+ Metronidazole+Tetracycline |
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When should you not use antibiotics in patients with H Pylori?
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Gastric adenocarcinoma
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When is an antacid appropriate?
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Mild, occasional GERD symptoms
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Antacids with strongest mEq ANC and lowest tablet number
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Maalox and Mylanta Double Strength
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PPI side effects
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Risk of fracture with longterm use
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Ulcer Treatment
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Clarithromycin Triple Therapy:
PPI+ Clarithromycin+ Amox/Metronidazole Bismuth Quad. Therapy: PPI/H2RA+ Bismuth+ Metronidazole+Tetracycline |
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When should you not use antibiotics in patients with H Pylori?
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Gastric adenocarcinoma
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When is an antacid appropriate?
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Mild, occasional GERD symptoms
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Antacids with strongest mEq ANC and lowest tablet number
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Maalox and Mylanta Double Strength
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Negative effect of many aluminum antacids like maalox and mylanta?
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Absorb and chelate many drugs
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Bismuth Compounds
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No acid neutralizing or inhibiting
Bacteriostatic and Bacteriocidal effects against H Pylori by increasing prostaglandins or modulating immune response |
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Side effects of Bismuth Compounds
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Black stools and darkening tongue
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Sucralfate
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Acts on lining of stomach and duodenum
Binds to and coats ulcers Acidic pH promotes dissociation to negatively charged compound that binds positively charged proteins Omeprazole superior for GERD Works as well as H2RAs for ulcers |
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Misoprostol
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Prevents NSAID induced gastric ulcers
Causes increased mucous production and decreased pepsin production |
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Side effects of Misoprostol
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Diarrhea
Abortion or birth defects so don't use in pregnant women Only for NSAID ulcers (not H Pylori) |
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Treatments for GERD
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PPIs
Coating Agents (Sulcralfate) Promotility/prokinetic agents (Promotility agents have most side effects and don't work as well as PPIs for most) |
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Metoclopramide
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Accelerates gastric emptying
Mediated by muscarinic activity Side effects similar to other dopamine antagonists (Hyperprolactinemia and Parkinsonian effects) |
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Bethanechol
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Parasympathetic choline ester that stimulates muscarinic receptors
Contraindicated in patients with asthma, peptic elcer and incontinence |
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Cisapride
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Serotonin agonist
Increases muscle tone in esophageal sphinter |
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Zollinger Ellison Syndrome
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Tumor of pancreatic islets that produces gastrin in large quantities
Treat with PPI |
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Stool Softeners
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Act as detergeants to allow mixing of water, lipids, and fecal matter
Also increases secretions in intestine Softens feces within 1-3 days |
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Lubricant/Emollient
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Works in colon beginning in 6-8 hrs.
Make stool slippery for better sliding Mineral Oil is ex. and also retards colonic water absorption (potential for fat malabsorption) |
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Osmotic Laxatives
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Act on colon in 0.5-3 hrs
PEG solution and electrolytes are used for whole bowel irrigation before colonoscopy |
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Most common cause of secretory diarrhea
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Cholera toxin stimulating anion secretion
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Loperamide and Diphenoxylate
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Opiates that decrease motility
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Mehanism of Albendazole and side effects
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Binds beta tubulin of parasite to inhibit polymerization
Effects: short term are GI and dizziness; long term elevation of liver enzymes |
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Antihelminth used for tropical filariasis (Wuchereria, Brugia, Loa)
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Diethylcarbamazine
*Contraindicated in river blindness |
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Mehanism of Albendazole and side effects
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Binds beta tubulin of parasite to inhibit polymerization
Effects: short term are GI and dizziness; long term elevation of liver enzymes |
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Atihelminth used for Strongyloides and Oncocera
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Ivermectin
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Antihelminth used for tropical filariasis (Wuchereria, Brugia, Loa)
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Diethylcarbamazine
*Contraindicated in river blindness |
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Mechanism for Ivermectin
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Increases GABA transmission to paralyze the microfilaria
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Atihelminth used for Strongyloides and Oncocera
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Ivermectin
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Antihelminth that treats schistosomiasis, liver flukes and adult tapeworms
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Praziquantel
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Mechanism for Ivermectin
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Increases GABA transmission to paralyze the microfilaria
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Antihelminth that treats schistosomiasis, liver flukes and adult tapeworms
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Praziquantel
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Mechanism of Praziquantel
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Increases Ca Permeability for Paralysis
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Mechanism of use of Pyrantel Pamoate
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Use for intestinal worms with heavy worm burden
Kills larva by increases Ach and paralyzing |
