GI pharm Flashcards
GERD and PUD
H2 receptor antagonists
PPI
mucosal protectants
antacids
antiemetics
increase protective factors
antacids
sucralfate
decrease aggressive factors
H. pylori
target gastric acid secretion: H2 blockers and PPI (parietal cells)
H. pylori tm
several abx and gastric acid I
combo therapy to minimize resistance (likes acidic env and most abx dont thrive well there)
need confirmed case before treating bc resistance
10-14 days, adherence not great bc v expensive and up to 12 pills/day
cimetidine
famotidine
h2 receptor antagonists
moa: block h2 receptors in stomach, reduce gastric acid secretion 60-70%, increases stomach pH
PO, IV at least 1 hr apart from antacids, OTC
I: GERD, PUD, ulcer prophylaxis - asp pna, heartburn/dyspepsia
h2 receptor antagonists: SE
well tolerates, CNS effects in elderly, slight increased risk of pna in elderly
interactions: inhibit cyp450 (cimetidine, thats why famotidine is used 1st line)
can increase warfarin, phenytoin, theophylline bc cyp450 I (esp cimetidine)
give IV slowly to avoid bradycardia
PPIs
omeprazole
patopracole
esomeprazole
moa: bind PP, inhibit H/K ATPase enzyme system (proton pump), irreversibly inhibits secretions of HCl - primary driver for stomach acid secretion
more effective than H2RA
I: short term treatment of PUD and GERD
PPI SE
short = safe
long (years) = increased risk of pna, bone loss/hip fracture, stomach cancer, benefits outweigh risks for most
few interactions
mucosal protectant
sucralfate
sucrose base, aluminum hydroxide
moa: alters when exposed to gastric acid, sticky thick gel -> protective barrier
I: duodenal ulcers, gastric ulcers, chronic gastritis
PO - tablet or suspension, take before you eat
sucralfate: SE
no major
may cause C
decrease drug abs, PO take 2 hrs apart
antacids: SE
Al and Ca based = c
Mg based = d
Mg + Al = balanced
acid rebound
chelation, altered gastric abs of many drugs (separate by 2hr)
antacids
moa: neutralize acid by approximately 50%
I: PUD (heal), GERD (s), stress ulcers (prophyl), heartburn and indigestion (for some)
antiemetics
serotonin blockers
antihistamines
anticholinergics
dopamine antagonists
prokinetics
ondanestron
serotonin blocker
moa: block serotonin receptors in chemoreceptor trigger zone in brain and in afferent vagal nerves in stomach and SI
PO or IV
I: n/v, esp in chemo/radiation
ondanestron: SE
common
mild HA, d, dizzy, c
serotonin S
be aware of other drugs that affect serotonin (SSRI, SNRI, TCA, MAOIs, buspirone, tramadol)
antihistamines
dimenhydrinate
meclizine
hydroxyzine
moa: block release of histamine H1 receptors in inner ear
I: treat dizzy and n -> antiemetics and antivertigo associated with motion sickness
antihistamines: SE
sedation, drowsy, dizzy
anticholinergic effect!
FALL RISK - esp elderly
not given IV -> tissue necrosis, gangrene
dopamine antagonists
prokinetic agent = metoclopramide
moa: block dopamine receptors, increase tone of lower ES (GERD), increase peristalsis in stomach and intestine (diabetic gastroparesis and post op)
I: n/v associated with chemo/radiation/opioids, GI motility issues, paralytic ileus
dopamine antagonists: SE
sedation
severe: extrapyramidal symptoms, restlessness, neuroleptic malignant S
extrapyramidal s
drug induced movement disorders
metoclopramide + antipsychotic meds
akathisia: may feel restless, tense, constant desire to move
acute dystonia: invol muscle contractions
parkinsonism -> rigid muscles in limbs
tardive dyskinesia -> late onset, progressive S, repetitive facial movements - tongue twisting, cheek puffing, chewing motions, lip smacking, grimacing
neuroleptic malignant S -> worst, life threatening, muscle rigid 1st, fever, drowsy, confusion -> seizure
drug therapy for diarrhea
diphenoxylate with atropine
loperamide
moa: decrease intestinal peristalsis, reduce intestinal effluent
SE: drowsy and c
fall and driving precautions esp with other CNS depressants
anticholinergic effects of atropine
serious: cardiac arrest/arrythmias (brady)
IBS meds
5 aminosalicylates
DMARDs
not great at treating
5 aminosalicylates
sulfasalazine
I: mild - mod IBS
moa: sulfonamide abx that converts intestine into 5 aminosalicyclic acid AND sulphapyridine
sulphapyridine has no therapeutic effect for IBD because of its SE some pt prefer mesalamine alone
sulfasalazine: SE
n, fever, rash, HA, hematologic disorders
dont give to pt with sulfa allergy or who have certain types of anemias, caution for use in pt with many diseases - can cause lots of issues
DMARDs
infliximab
disease modifying antirheumatic drug
moa: monoclonal antibody that neutralizes TNF alpha (inflam mediator)
I: lots, IBD
infliximab: SE
immune suppression: infection, cancer, HF, infusion rxn, neutropenia
often require therapeutic drug monitoring and biomarker monitoring for inflam (CRP)
screened for TB and other diseases before start, titers drawn, need vax
general tm
diet mod, sx, pharm
bismuth subsalicylate
adsorbent
Coats walls of GI tract, bind causative agent for elimination (adsorption)
I: diarrhea
SE: Increased bleeding time, constipation, dark stools and tongue darkening
Same as aspirin
nc: Form of aspirin
Activated charcoal also given in drug overdose
Loperamide (otc, slowed peristalsis only, no SE)
Diphenoxylate (with anticholinergic, Rx)
antimotility
moa: Slow peristalsis by reducing rhythmic contractions and smooth muscle tone of GI tract, drying effect due to anticholinergic – reduce gastric secretions
I: d
SE: Due to anticholinergic: Urinary retention, headache, dizziness, anxiety, drowsiness, bradycardia, hypotension, dry skin, flushing
nc: Used alone or in combo with adsorbents and opiates
Lactobacillius organisms (Bacid, Culturelle)
Saccharomyces boulardii (C. diff)
probiotics
moa: replenish bacteria and restore normal flora
I: d r/t abx, S. b is for C. diff
nc: these bacteria make up majority of normal flora of gut, OTC or Rx strength
Docusate sodium
Mineral oil
Emollient
moa: Both prevent water from moving out of intestines
DS - Lubricate fecal material and walls, promote fat absorption into fecal mass (soften stool)
MO - lubricate intestines
I: DS- Prevent opioid induced constipation
MI - fecal impaction
SE: Skin rashes, decreased absorption of vitamins
NC: DS - given prophylactically for post op
MI - PO and PR (rectal) or enema
psyllium
Bulk forming laxatives
moa: Act similar to dietary fiber, absorb water into intestine – increasing bulk (volume), distend bowel to initiate flex bowel activity and bowel movement
I: Okay for long term use
Contraindicated for intestinal obstruction or fecal impaction
SE: Impaction above strictures, fluid/electrolyte (less than other types of laxatives) imbalance, gas formation, esophageal blockage
nc: Action limited to GI tract – no systemic affects
Take with lots of water to prevent esophageal obstruction or fecal impaction (should be in 8-12 oz of water)
Glycerin
Lactulose
Polyethylene glycol
hyperosmotic
moa: Increase water content in feces; promote distension, peristalsis, and evacuation
L: works in colon; reduce blood ammonia levels
I: G - common in children – suppository
L - reduce blood ammonia levels – use with liver disease and hepatic encephalopathy
PG - before diagnostic or surgical bowel procedures – total cleansing of bowel, very potent
SE: Abdominal bleeding, rectal irritation, electrolyte imbalance
Magnesium salts (Mg citrate, Mg hydroxide, Mg sulfate)
Sodium salts
Saline
moa: Increase osmotic pressure and draw water into colon
I: Constipation
SE: Magnesium toxicity (in renal pts), electrolyte imbalance, cramping, diarrhea
nc: Work within 3-6 hrs
Mg salts available OTC
Na salts usually given via fleet enema
bisacodyle
senna
I: Constipation or whole bowel evacuation – work on entire GI tract
SE: Nutrient malabsorption, gastric irritation, e imbalance
NC: B - PO and PR
OTC
