GI Diseases Flashcards
What four criteria should be considered when treating ulcers?
- relief of symptoms
- promotion of healing
- prevention of complications
- prevention of recurrence
When treating ulcers, what drugs are used with the goal of neutralizing acid?
Antacids: calcium carbonate, sodium bicarbonate, magnesium hydroxide or carbonate, aluminum hydroxide
- all relieve pain and achieve faster healing
- elevate gastric pH to at least 5 to reduce proteolytic action of pepsin
Which antacid is useful in patients with renal failure?
aluminum hydroxide
When treating ulcers, what drugs are used with the goal of decreasing acid production?
Anticholinergics, H2 blockers, H/K ATPase inhibitors
- all of these work directly on the parietal cell
What are the anticholinergic drugs used to treat ulcers and what are their side effects? Contraindications?
atropine, propantheline, and metantheline bromide
- adverse effects: dry, blurred vision, constipation, drowsiness, mental confusion
- CI: pyloric obstruction, hiatal hernia, peptic esophagitis
What histamine receptor blockers are used to treat ulcers? What are adverse effects? What should you be aware of when stopping them?
Cimetidine, ranitidine, famotidine, nizatidine (all competitive inhibitors)
- adverse effects: HA, lethargy, confusion, p450 interactions
- during use, parietal cell will upregulate histamine receptors, so have to stop use of H2 blockers gradually
What H/K ATPase inhibitors are used to treat ulcers? What are the adverse effects?
omeprazole, lansoprazole, rabeprazole, esomeprazole, pantoprazole, dexlansoprazole (all are noncompetitive inhibitors)
- these drugs are activated by acid pH, and exhibit better pain relief and faster healing than H2 blockers
- adverse effects: HA, gynecomastia, inhibition of P450
Which H/K ATPase inhibitor exhibits the least interaction with other drugs? Which exhibits the most interaction?
pantoprazole (least - lowest P450 inhibition)
omeprazole (most - highest P450 inhibition)
Which drugs increase mucosal resistance by directly coating the ulcer crater?
bismuth salts - precipitates out in acid environments, lower ulcer recurrence than H2 blockers
sucralfate - binds to ulcerated tissues, as effective as H2 blockers
Which drugs increase mucosal resistance as prostaglandin E2 analogs?
misoprostol - decreases acid production, increases mucous and bicarbonate secretion
- best effect is seen if patients are on NSAIDs (used for prevention of long term NSAID induced ulcers)
- adverse effects: diarrhea, cannot use in pregnancy
Which drugs are used to eradicate H. pylori?
bismuth salts, metronidazole + tetracycline or amoxicillin
What is triple therapy for H. pylori?
- PPI (2x/day)
- add 2 of: amoxicillin, clarithromycin, metronidazole (2x/day)
What is quadruple therapy for H. pylori?
- PPI (2x/day)
- tetracycline (4x/day)
- bismuth subsalicylate (4x/day)
- metronidazole (3x/day)
What are lifestyle modifications that can be suggested in the treatment of GERD?
elevate head of bed, avoid food or liquid 2-3 hrs before bed, avoid fatty or spicy foods, avoid cigarettes and alcohol, take a liquid antacid
What drugs are used to treat persistent GERD symptoms without esophagitis?
- alginic acid antacids (simethacone, magnesium)
- promotility drugs (cisapride, metoclopramide, reglan)
- H2 blockers (cimetidine, ranitidine, famotidine, nizatidine)
What treatments are used for persistant GERD with esophagitis? What must you be sure of before you start treatment?
- make sure there is no Barrett’s or cancer present
- H2 blockers
- promotility drugs
- H/K ATPase inhibitors (PPIs)
- antireflux surgery
How do promotility drugs work?
- enhance gastric emptying and increase the tone of the LES
- metoclopramide is a local dopamine antagonist
- cisapride is associated with risk of sudden cardiac death
- reglan has the adverse effect of tremor
Which antiemetics have actions on the chemo receptor trigger zone in the medulla and are considered phenothiazines?
- prochlorperazine (dopamine antagonist with side effects of torticollis)
- promethazine (H1 blocker, anticholinergic with side effect of somnolence)
Which antiemetics have actions on the chemo receptor trigger zone in the medulla and are considered benzamide derivatives?
- trimethobenzamide (pediatrics)
- metochlopramide (dopamine antagonist, SE tremor)
Which antiemetics have actions on the chemo receptor trigger zone in the medulla and are considered 5HT3 antagonists?
- ondansetron (most commonly prescribed)
- granesitron and dolasetron (used for anesthesia induced emesis)
- all have adverse effects of HA, dizziness, somnolence
How does tetrahydro cannabinol work as an antiemetic?
anticholinergic
What drugs are used to treat gastro paresis (outlet obstruction or loss of gastric tone), as seen in diabetes mellitus?
- promotility drugs (metochlopramide, cisapride, domperidone)
What drugs are used to treat diarrhea by decreasing GI secretion or motility?
- anticholinergics (atropine sulfate)
- opioid agonists ( loperamide, diphenoxylate, codeine sulfate)
- loperamide - safest for traveler’s diarrhea
- dephenoxylate/codeine - don’t give to kids!
What are the colloids and pectins and how do they work?
metamucil and kaopectate, respectively
- absorb water, but don’t prevent potential dehydration (bulk up stool and decrease incontinence/feeling of urgency)
What is the treatment of constipation?
- irritants or stimulants (castor, senna, bisacodyl)
- osmotic cathartics (magnesium, lactulose for liver failure, milk of magnesia)
- bulk-forming (psyllium, methycellulose)
- lubricant and fecal softeners - might use with stimulant (dioctyl sodium succinate, poloxalkol)
What antiinflammatory drugs are used acutely for IBD?
- mesalamine - ulcerative colitis
- sulfasalazine - ulcerative colitis
- olsalazine - ulcerative colitis
- also, corticosteroids and antibiotics
What immunosuppressive drugs are used chronically for IBD?
- azathioprine - purine antimetabolite that interferes with DNA synthesis
- corticosteroids
- infliximab - neutralizes TNFa
- cyclosporine - suppresses T helper and T suppressor lymphocytes
What are drug options for treating irritable bowel syndrome?
- bulk forming agents (metamucil, fibercon)
- opioids (loperamide)
- anticholinergics
- antidepressants (5HT3 antagonist alosteron for diarrhea predominant, 5HT4 antagonist tegaserod maleate for constipation predominant)
