USMLE (Fach) / Pharmacology - Gastrointestinal (Lektion)
In dieser Lektion befinden sich 35 Karteikarten
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- Histamine-2 blockers Cimetidine, ranitidine, famotidine, nizatidineTake H2 before you dine. Mechanism: Reversible block of histamine H2-receptors → ↓ H+ secretion by parietal cells Clinical use: Peptic ulcers, gastritis, ...
- Antacids Preparations that neutralize gastric acid. - Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying. - All can ...
- Bismuth, sucralfate Mechanism: Bind to ulcer base, providing physical protection and allowing HCO3- secretion to reestablish pH gradient in the mucous layer. Require acidic environment; usually not given with PPIs/H2 blockers. ...
- Misoprostol PGE1 analog. ↑ production and secretion of gastric mucous barrier, ↓ acid production. Clinical use: Prevention of NSAID-induced peptic ulcers (NSAIDs block PGE1 production).- Also used off-label ...
- Octreotide Long-acting somatostatin analog; inhibits secretion of various splanchnic vasodilatory hormones. Clinical use: - Acute variceal bleeds- Acromegaly- VIPoma- Carcinoid tumors Adverse effects:- Nausea, cramps, ...
- Osmotic laxatives - Magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose Mechanism: Provide osmotic load to draw water into the GI lumen Clinical use: Constipation- Lactulose also treats hepatic encephalopathy ...
- Sulfasalazine Combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory).- Activated by colonic bacteria (effect restricted to colon). Clinical use: Ulcerative colitis, Crohn disease ...
- Loperamide Agonist at µ-opioid receptors; slows gut motility. - Poor CNS penetration (low addictive potential). Clinical use: Diarrhea Adverse effects: Constipation, nausea.
- Ondansetron 5-HT3 antagonist; ↓ vagal stimulation. Central-acting antiemetic. Clinical use: Control vomiting postoperatively and in patients undergoing cancer chemotherapy. Adverse effects: QT interval prolongation, ...
- Metoclopramide D2 receptor antagonist. ↑ resting tone, contractility, LES tone, motility, promotes gastric emptying. - Does not influence colon transport time. Clinical use: Diabetic and postsurgery gastroparesis, ...
- Orlistat Inhibits gastric and pancreatic lipase → ↓ breakdown and absorption of dietary fats. Clinical use: Weight loss Adverse effects: Steatorrhea, ↓ absorption of fat-soluble vitamins, abdominal pain, ...
- Ursodiol (ursodeoxycholic acid) - Nontoxic bile acid. ↑ bile secretion, ↓ cholesterol secretion and reabsorption Clinical use: Primary biliary cirrhosis, gallstone prevention or dissolution
- Sucralfate - polymerizes on gastrointestinal luminal surface to form a protective gel-like coating of ulcer beds - requires acid pH (antacids may interfere) - ↑ healing- ↓ ulcer recurrence
- Proton pump inhibitors Omeprazole, lansoprazole, esomeprazole, pantoprazole, dexlansoprazole Irreversibly inhibit H+/K+ ATPase in stomach parietal cells. Clinical use: Peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison ...
- Laxatives Indicated for constipation or patients on opiates requiring a bowel regimen Bulk-forming laxatives: Psyllium, methylcelluloseOsmotic laxatives: Magnesium hydroxide, magnesium citrate, polyethylene glycol, ...
- Aprepitant Substance P antagonist. Blocks NK1 (neurokinin-1) receptors in brain. Clinical use: Antiemetic for chemotherapy-induced nausea and vomiting.
- Cimetidine Histamine-2 blocker Adverse effects:- Potent inhibitor of cytochrome P-450 (multiple drug interactions)- Antiandrogenic effects (prolactin release, gynecomastia, impotence,?libido in males)- Can cross ...
- Ranitidine Histamine-2 blocker
- Famotidine Histamine-2 blocker
- Nizatidine Histamine-2 blocker
- Aluminium hydroxide Antacid Adverse effects:- Constipation - Hypophosphatemia- Proximal muscle weakness- Osteodystrophy- Seizures
- Calcium carbonate Antacid Adverse effects:- Hypercalcemia (milk-alkali syndrome)- Rebound acid ↑- Can chelate and ↓ effectiveness of other drugs (eg, tetracycline)
- Magnesium hydroxide Antacid Adverse effects:- Diarrhea- Hyporeflexia- Hypotension- Cardiac arrest
- Bulk-forming laxatives Psyllium, methylcellulose Mechanism: Soluble fibers draw water into gut lumen, forming a viscous liquid that promotes peristalsis. Adverse effects: Bloating
- Osmotic laxatives Magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose Mechanism: Provides osmotic load to draw water into GI lumen Adverse effects:- Diarrhea, dehydration; may be abused by bulimics - ...
- Stimulants Stimulants: Senna Mechanism: Enteric nerve stimulation → colonic contraction Adverse effects: Melanosis coli
- Emmolients Docusate Mechanism: Promotes incorporation of water and fat into stool.
- Docusate Emmolient laxative
- Senna Stimulant laxative
- Magnesium citrate Osmotic laxative
- Polyethylene glycol Osmotic laxative
- Lactulose Osmotic laxative
- Methylcellulose Bulk-forming laxative
- Psyllium Bulk-forming laxative
- Penicillamine A metal-chelating agent that facilitates the renal excretion of heavy metals by forming water-soluble compounds. - Used in the treatment of copper, lead, and mercury poisoning. - Also used as an antifibrotic ...