GI Flashcards
Antacids
- What are the different formulations?
- Which ones have the highest reduction in stomach acid?
- What time period should antacids be separated from other medications?
- Formulations: aluminum hydroxide, magnesium hydroxide, calcium carbonate
- Magnesium and calcium carbonate have the highest reduction in stomach acid
- At least 2 hours
Antacids
Indications & Pharmacodynamics
- Indications: hyperacidity, PUD, GERD
- Pharmacodynamics: weak bases that interact with HCl in your stomach to reduce gastric acidity and increase pH
- If ingested in a fasting state antacids will reduce acidity for 20-40 minutes
- If administered one hour post-meal, will last about 2-3 hours
- Minimally absorbed - calcium based will have increased absorption when taken with Vit D
Antacids
Caution/contraindications: when to avoid, caution, pregnancy & adverse fx (2)
- Avoid: aluminum and magnesium based in renal impairment or renal insufficiency;calcium based in hypercalcemia or renal calculi; abdominal pain of unknown etiology
- Caution: sodium restriction
- Compatible with pregnancy and lactation
- Adverse fx: aluminum and calcium based can cause constipation; magnesium based can cause diarrhea
Cytoprotective agents
Sucralfate
Indications & Pharmacodynamics
Indications: prophylaxis and tx of duodenal ulcers associated with NSAID use and tx for duodenal ulcers from other causes
Pharmacodynamics: selectively binds to necrotic ulcer tissue, covering it and acting as a barrier for outside stimuli such as acids
Cytoprotective agents
Sucralfate
Caution/contraindications: catuion, pregnancy, peds, other considerations & adverse fx (3)
- Caution: geriatric patients with CrCl less than 30ml/min
- Pregnancy/lactation: OK
- Peds: avoid - limited data
- Other considerations: Take on an empty stomach; separate from other meds by 2 hours
- Adverse fx: constipation, dizziness, gastric discomfort
Cytoprotective agents
Misoprostol
Indications & Pharmacodynamics
- Indications: prophylaxis and tx of duodenal ulcers associated with NSAID use
- Pharmacodynamics
- Inhibition of gastric secretion through inhibition of histamine stimulated by cAMP
- Mucosal protective qualities by increasing mucus and bicarbonate
Cytoprotective agents
Misoprostol
Caution/contraindications: caution, pregnancy, peds, other & adverse fx (5)
- Caution: renal impairment
- Pregnancy/lactation: Avoid
- Peds: avoid - limited data
- Other: Take with food
- Adverse fx: diarrhea, abdominal pain, nausea, postmenopausal bleeding, headache
Histamine 2 Agonists
Ranitidine, Famotidine, Cimetidine
Indications & Pharmacodynamics
- Indications: mild intermittent GERD, PUD, heartburn
- Pharmacodynamics: reversible competitive inhibition of histamine at H2 receptors of the gastric parietal cells, thus inhibiting gastric acid secretion; gastric acid secretion reduced by 35-50%
- Onset 30 minutes
- Can be taken PRN
Histamine 2 Agonists
Ranitidine, Famotidine, Cimetidine
Which medication of the three is most commonly used and why?
- Famotidine: considered the safest so used most commonly
- Ranitidine has been removed from the market due to occurrence of hepatitis
- Cimetidine has excess adverse fx and risks do not typically outweigh benefits
Histamine 2 Agonists
Famotidine
Caution/contraindications: caution, pregnancy, peds & adverse fx (7)
- Caution: renal impairment
- Pregnancy/lactation: OK
- Peds: OK
- Adverse fx: headache, dizziness, confusion, agranulocytosis, granulocytopenia, thrombocytopenia, aplastic anemia
Proton pump inhibitors
Omeprazole, pantoprazole, esomeprazole
Indications & Pharmacodynamics
- Indications: duodenal and gastric ulcers, erosive gastritis, Zollinger-Ellison syndrome, GERD (when sx no longer mild and intermittent)
- Pharmacodynamics: reduce acid secretion by more than 90%; inhibit gastric proton pumps - H/K-ATPase pump, located on the parietal cells to suppress acid secretion
- Take 30-60 minutes before meal, preferably before breakfast
- Last 72 hours, but slow onset
Proton pump inhibitors
Omeprazole, pantoprazole, esomeprazole, lansoprazole, rabeprazole
Caution/contraindications: black box warning, caution, pregnancy, peds (different ages for each medication)
- Black box warning for omeprazole and clopidogrel - reduces effectiveness of clopidogrel
- Caution: elderly and those with hepatic dysfunction
- Pregnancy/lactation: OK
- Approved in peds
- esomeprazole, omeprazole, lansoprazole - short term use for children 1+
- pantoprazole ok for 5+
- rabeprazole ok for 12+
Proton pump inhibitors
Omeprazole, pantoprazole, esomeprazole
Adverse fx (4)
What does long term use predispose a person to? (4)
Adverse fx: nausea, diarrhea, HA, abdominal pain
long term use: risk for bone fractures, C.diff infections, hypomagnesemia, Vit B12 deficiency
Antimotility agents
Diphenoxylate/atropine
Pharmacodynamics & adverse fx (6)
pharmacodynamics: inhibits excessive GI motility and GI propulsion; atropine added, provides anticholinergic fx that decrease secretion in the bowel and slow peristalsis
Adverse fx: dry mouth, dry eyes, urinary retention, blurred vision, drowsiness, dizziness
Antimotility agents
Diphenoxylate/atropine
Caution/contraindications: caution, contraindication, pregnancy, peds, other
- Caution: liver/kidney disease, pts with bowel infection- fever, bloody stool, fecal leukocytes, BPH, elderly
- Contraindicated: narrow-angle glaucoma
- Pregnancy: caution
- Peds: 12+ ok
- Other considerations: Class V controlled substance, high doses can cause euphoria and physical dependence
Antimotility agents
Loperamide
Pharmacodynamics & adverse fx (4)
- Pharmacodynamics: acts through opioids receptors to inhibit peristalsis and prolong gastric time; reduces fecal volume and diminishes loss of fluid and electrolytes
- Adverse fx: abdominal discomfort, constipation, drowsiness, dry mouth