peptic ulcer disease (acid) Flashcards
stomach secretions
- hydrochloric acid (parietal cells)
- pepsinogen (chief cells)
- mucus
- bicarbonate
- prostaglandins
parietal cells
produce and secrete HCl to keep stomach pH at 1-2
- primary site of action for many acid-controller drugs
ECL cells
secrete histamine
- stimulate parietal cells
stomach acid related diseases
action of acidity of digestive tract integrity
lay terms for stomach problems (indigestion, sour stomach, heartburn, acid stomach)
- PUD: peptic ulcer disease
- GERD: gastroesophageal reflux disease
aggressive factors against stomach (makes ulcers)
- h. pylori
- NSAIDs
- acid
- pepsin
- smoking
defensive factors for stomach (protect from ulcers)
- mucus
- bicarbonate (neutralize)
- blood flow
- prostaglandins
what do PUD drug therapies do?
- eradicate h.pylori if present in stomach
- reduce gastric acidity
- enhance mucosal defences
treat ulcer but also prevent it from happening in the future
h pylori
helicobacter pylori
- 90% duodenal ulcers, 70% gastric ulcers
- antibacterials eradicate it
- recurrence rates much less with eradication
- releases its own chemicals to protect from acid
inhibitors of gastric acid secretion/action
- H2 antagonists
- Proton pump inhibitors
- antacids (Mg, Ca, Al salts)
- other agents: protect. mucosa
H2 antagonists
histamine 2 receptors: inhibit production of acid
- reduce acid secretion
- OTC in low dose
- most popular
H2 antagonist examples
- cimetidine (adverse effects)
- famotidine
- ranitidine
- nizatidine
H2 antagonist mechanism of action
block h2 receptors of acid-producing parietal cells
- decreased HCl production
- allows ulcer to heal due to less acidity
H2 antagonist indications
- GERD - erosive esophagitis
- PUD
- adjunct therapy in control of upper GI bleeding
- pathological gastric hypersecretory conditions
H2 antagonists adverse effects
low incidence of AE
- cimetidine may induce impotence and gynecomastia (antiandrogenic effect - sex hormones)
- in elderly may see CNS depression (lethargy), confusion because of renal/hepatic impairment
H2 antagonists drug interactions
Cimetidine
- inhibits liver cytochrome p-450
- affect metabolism of other drugs causing increased drug levels (warfarin - increased bleeding)
H2 antagonist client implications
cimetidine:
- care in pt with impaired renal/liver function (metabolism and excretion)
- caution with pt who are confused, disoriented, elderly
- do not take with antacids, affects absorption (take at least an hour apart)
proton pump inhibitors (PPI)
inhibit production of acid
- inhibition of the pump that moves H+ ions into stomach lumen (acidity)
- more effective than H2 antagonists
PPI mechanism of action
- irreversibly bind to H+/K+ ATPase enzyme pump
- normal acid secretion now requires parietal cell to make new atpase
PPI examples
- omeprazole
- lansoprazole
- rabeprazole
- pantoprazole
- esomeprazole
omeprazole
enteric coated (avoid being broken down by acid in stomach to it can be absorbed in small intestine)
- broken down by acid
- absorbed in small intestine into circulation then brought to stomach
PPI indications
- GERD maintenance therapy
- erosive esophagitis
- short term treatment of active and benign gastric ulcers
- gastric-producing tumour (zollinger-ellison syndrome)
PPI adverse effects
safe for short term therapy (4-8 weeks)
- incidence low and uncommon
- headaches, GI (n&v, diarrhea)
- caution in pt with liver disease
PPI drug interactions
may inhibit absorption of drugs that require an acidic GI environment for absorption
- pH levels raised to drugs that need a low pH to be absorbed can’t be, pass through stomach
- ketoconazole (antifungal)
treatment for h pylori infection
triple therapy
- 2 antibacterials: amoxicillin + clarithromycin
- PPI: omeprazole
- 7-14 days
- 2 antibacterials reduce resistance development
client care: PPI
omeprazole:
- capsule swallowed whole (enteric coated - not crushed, opened or chewed)
- may be given with antacids
- short term treatment
antacids mechanism of action
chemically neutralize acid
- do not prevent acid production
- no absorbed into circulation, works in the lumen
- add on for PUD, not as good on its own
antacids examples
alone or in combination:
- aluminum salts
- magnesium salts
- calcium salts
- sodium bicarbonate
aluminum salts
- may cause constipation
- often used with magnesium salts to counteract constipation (cause diarrhea)
aluminum hydroxide
aluminum carbonate
magnesium salts
- commonly cause diarrhea
- used with other agents to counteract
- dangerous when used with renal failure (accumulation and kidneys not getting rid of it)
- magnesium carbonate, hydroxide, oxide, trisilicate
calcium salts
- may cause constipation
- possible kidney stones
- calcium carbonate
- often advertised as dietary carbonate
sodium bicarbonate
rare use
- highly soluble
- quick onset, short duration
- may cause metabolic alkalosis
- sodium content may cause problems in clients with HF, hypertension, or renal insufficiency
antacids adverse effects
minimal and depend of the compound used
- aluminum and calcium: constipation
- magnesium: diarrhea
- calcium carbonate: constipation, gas, belching (often combined with simethicone)
antacids drug interactions
absorption of other drugs:
- may reduce absorption of other drugs given at same time (H2)
chelation (binding together)
- chemical binding or inactivation of another drug
- produces insoluble complezes
- reduce absorption
- eg tetracycline
care implications antacids
assess for allergies and preexisting conditions that may restrict the use of antacids
- fluid imbalances, renal disease, HF, pregnancy, GI obstruction
client with HR or hypertension should use low-sodium antacids
client implications antacids cont
- root cause of many drug interactions
- give meds 1-2 hours after antacid
- antacids may cause premature dissolving of EC meds
- administer with 240 ml h20 to enhance dispersion
- caffeine, alcohol, harsh spices, and black pepper may aggravate underlying GI condition
other agents: protect mucosa
- sucralfate: bind directly to ulcer surface
- misoprostol: prostaglandin agent
sucralfate
- cytoprotective agent
- used for intestinal erosions
- forms gel with mucus in low pH
- attracted to and binds to base of ulcers and erosions forming a protective barrier
- protects cells and allows recovery
- inhibits pepsin
- do not administer with antacids
sucralfate cont
- little absorption from the gut
- may cause constipation, nausea, and dry mouth
- may impair absorption of other drugs (tetracycline, digoxin), sticks to drugs and makes them less effective
- binds with phosphate (may be used in chronic renal failure to reduce phosphate levels)
misoprostol
synthetic prostaglandin
- does job of PGI2 and PGE2
prostaglandins have cytoprotective activity
- produce mucus and bicarbonate (neutralize)
- reduce acid secretion
- promote local cell regeneration
- help to maintain mucosal blood flow
misoprostol cont.
reduce gastric effects of NSAIDs (ASA, diclofenac)
- combination tablets (arthrotec = diclofenac + misoprostol)
not in pregnancy
- used to terminate pregnancy (smooth muscle constriction - medical abortion)
misoprostol adverse effects
abdominal cramps, diarrhea
- contraction of smooth muscle
