GI Drugs Flashcards
Meds that cause GERD,
calcium channel blockers, glucocorticoids, muscle relaxants, theophylline, oral bronchodialators, diazepam, nicotine, etoh, coffee, chocolate, mint, fatty foods
risk factors for ulcers
H. pylori, OTC pain meds (aspirin and ibu)
Etoh
Smoing
Family Hx
4 types of antacids
aluminum salts magnesium salts calcium salts sodium bicarbonate don't use antacids chronically
Aluminum Salts
constipating mag can counteract constipation aluminum toxicity aluminum carbonate (basaljel), hydroxide salt:AlternaGEL, combination with mag: Gaviscon, Maalox, Mylanta, Di-Gel
Magnesium salts
often cause diarrhea
dangerous with renal failure, can result in mag accumulation
Calcium Salts
may cause kidney stones
long duration of acid action can cause rebound hyperacidity
TUMS
stay away from it
Sodium bicarbonate
high solubility buffers acidic properties of HCL quick onset, short duration may cause metabolic alkalosis high sodium content (CHF, HTN, renal insuf)
ppi therapy should
elinimate symptoms
heal erosive esophagitis
prevent the relapse of erosive esophagitis
PPI
wait 2-6 weeks before increasing dose
OTC is more expensive than rx
hates esomeprazole
give 1h before meals
H2 receptor antagonist
reversible competitive inhibitor of H2 receptor
highly selective
effective in inhibiting nocturnal acid secretion
modest impact on meal stimulated acid secretion
ranitidine and famotidine are good,
cimetidine is bad P450 inhibitor, gynecomastia, impotence, decreased levels of other drugs (warfarin, theophylline, phentoin, ethanol)
take 1h before or after antacids
assess for allergies, imp renal or liver function
H2 antagonist SE
HA, lethargy, confusion, diarrhea, urticaria, sweating, flushing, other effects, may decrease absorption of drugs that need acidic GI env
kaolin and pectin
absorbent antidiarrheal, clay like powder attracts and holds onto bacteria, then thickens.for simple diarrhea, act locally in bowel
bismuth subsalicylate
antisecretory and antibacterial, possibly anti-inflammatory, part of h.pylori tx, contains aspirin, CI in kids and teenagers, gray/black stools and black tongue are normal
diphenoxylate with atropine
constipating, opioid activity at high doses, anticholinergic properties, slows peristalsis, d/c if abd distension, caution in older adults, hepatorenal disease
loperamide
binds to opiate receptors of the intenstinal wall, slow gastric motility, diminishes fluid loss, d/c if abd distension
oral rehydration solution
8 oz water, 1/4 tsp baking soda, alternate with water with salt and honey. for severe diarrhea, more salt is needed
IBD diarrhea control
steroids and sulfasalazine, loperamide first
traveler’s diarrhea
bismuth subsalicylate, oral antimicrobials, loperamide (immodium)
cytoprotective agents
sucralfate (basic aluminum salt)- viscous gel adheres to ulcer’s crater, stress ulcer prevention and duodenal ulcer, taken on empty stomach, avoid concurrent antacid, and misoprostol - stimulates mucous and bicarb secretion(caution in renal impairment) for NSAID induced problems, cat X, GI sx, with food
5 classes of antiemetics
antihistamines, phenothiazines, sedative hypnotics, cannabinoids, and 5_HT receptor antagonists
antihistamines
good for motion sickness, dimenhydrinate, diphenhydramine, hydroxyzine, and meclizine, strong anticholinergic effects, CI in severe liver disease, better for long term applications
phenothiazines
block dopamine receptors, sedating, have extrapyramidal effects (limiting), prochlorperazine and promethazine (fatal resp dep younger than 2, bone marrow depression)), metoclopramide (prokinetic), CI in Parkinson’s, narrow-angle glaucoma, bone marrow depression, severe CV or hepatic disease. some anticholinergic effects. may discolor urine pink/reddish-brown. additive hypontensive effects. CBC prior to initiating therapy, blood dyscrasias 4 to 10 weeks after therapy starts
cannabinoids
decrease n/v/appetite stimulant, works in the CNS, may lower seizure threshold, palpitations, tachycardia, hypotension, interacts with other CNS depressants
5-HT receptor antagonists
block serotonin on the peripheral vagal nerve terminals and centrally, used with chemotherapy, may mask progressive ileus, constipation, HA, fatigue
drugs that cause peptic ulcers
NSAID, glucocorticoids, cytotoxic agents
colloidal bismuth compounds
coats ulcer, stimulates mucus and bicaarb, direct action against H. pylori, blackening of tongue and stool, not for long term use - bismuth toxicity
IBD therapy
sulfasalazine and 5-ASA, (mesalamine, active molecule) 2 moeity’s, mild to moderate CD/UC
5-ASA delivery systems
Pentasa - esop-rectum, for Chrons’, slow release
Asacol-ileum and colon effected, 60-70%
Rowasa-if only rectal, avoids systemic
Colazal-very expensive, colon
antibiotics
CD only, not UC, metronidazole has anti-fistula properties, cipro, pouchitis biologics if metronidazole doesn’t work
steroids
for flare-ups, not long-term, hospitalize if can’t tolerate PO, if unable to taper, try antimetabolite or infliximab, topical can be used in rectum
azathioprine and 6 MP
for steroid dependent IBD, measure CBC q2w, takes months to work, major durg-drug ALLOPURINOL
methotrexate
IV for active CD or maitenance of CD remission, induction with steroid withdrawal, weekly IM, monitor CBC, LFT, renal function
cyclosporine
induction in UC, CD in high doses (toxicity), steroid refractory UC, used to bridge to AZA as maintenance
infliximab
tnf alpha antibody - CD and UC with inadequate response to conventional tx, withdrawal concomitant steroids. avoid infection, demyelinating d/o, CHF, malignancy, screen for
metoclopramide
stimulates motility in GI, postprandial and daytime heartburn, 30 min prior to meal, r/f tardive dyskinesia, don’t use more than 12 weeks or when GI motility is CI (obstruction), used for GERD and diabetic gastroparesis
PPI’s interfere with absorption of…
Warfarin, ketoconazole, digoxin, esters of ampicillin, iron salts. inc monitoring of INR. clopidogrel efficacy dec. by 50%. lansoprazole does not interfere with warfarin
tx of duodenal and gastric ulcers
PPI for 12 weeks, once daily in the am before meals, also test for H. pylori
GERD management
lifestyle and antacid PRN, then H2RA, then PPI. If refractory after 4-8 weeks, inc. PPI. if symptoms gone, decrease PPI after 4 weeks. if no relief after BID, referral to gastroenterologist or if endoscopy shows erosive disease. failure to achieve symptom relief after 3 months, gastroenterology referral.
alarm symptoms that require endoscopy
dysphagia, painful swallowing, noncardiac chest pain, weight loss, hematemesis, and choking. PPI may mask gastric CA.
stimulant laxatives
release of prostaglandins inc cAMP concentration increases secretion of electrolytes stimulates peristalsis rapid response, short term cascara (has etoh, CI pregnancy), senna, bisacodyl, and castor oil used for reduced mobility, constipating drugs, reduced motility, ibs, neurogenic bowel caution with severe CV disease
osmotic laxatives
draw water into intestinal lumen to inc pressure
hypertonic salt-based solutions
cause diffucion of fluid from the plasma inot the intestine
most powerful
mag hydroxide, mag citrate, PEG (CI in kids d/t electrolyte probs), used for bowel prep
CI in renal insufficiency, hyper mag, hypocalcemia, heart block
bulk producing laxatives
most physiological, safest,
natural and semisynthetic polysaccharides and cellulose
mechanical distention that increases peristalsis
long-term management of simple, chronic const
useful in avoiding straining to stool
mgt of chronic, watery diarrhea
CI narrowed esophageal or intestinal lumen and impaction
watch for sugar or salt
lubricants
mineral oil, retards colonic absorption of fecal water and softens stool
used with fecal impaction
lubricates intestines
may decrease absorption of fat soluble vitamins, avoid in pregnancy
r/f aspiration under 4 y.o.
surfactants
stool softeners, emollient action, good for hard, dry stool, anorectal conditions, painful stool, avoiding straining, safe for all ages.
no specific CI
CI of all laxatives
presence of n/v or undiagnosed abd pain or bowel obstruction.
miscellaneous
glycerin is local irritant, hyperosmotic, draws water. lactulose, hyperosmotic transformed to lactic acid and acetic and formic acid, lowers pH of colon. glycerin, for fecal impaction, neurogenic bowel.
hyperosmolar considerations
lactulose causes hyperglycemia, caution in presence of volume depletion,
chronic use of laxatives
r/f abuse and dependency, fluid and electrolyte imbalances, steatorrhea, osteomalacia, and vit and min deficiencies.
