GI system pharmacology

histamine 2 receptor antagonists

ranitidine, cimetidine, famotidine

action: blocks H2 receptors in the stomach lining which reduces secretion of stomach acid allowing ulcers to heal

uses: ulcers, GERD, heartburn, aspiration prophylaxis, indigestion, H pylori

complications: androgen blockage in males, CNS effects, constipation, diarrhea

contraindications: use cautiously in older adults (dizziness, drowsiness, confusion), COPD (acid suppression causes increased r/f pneumonia), and interferes with warfarin and antacids

nursing: avoid taking antacids at the same time (seperate by 1 hour), monitor for endocrine effects in men, mental status changes in older adults, avoid caffeine, alcohol, spicy foods, and smoking

proton pump inhibitors

omeprazole, pantoprazole, lansoprazole, esomeprazole

action: reduces gastric acid; more powerful and effective than H2 blockers

uses: ulcers, erosive esophagitis, GERD, hypersecretory conditions, sometimes given with antibiotics

complications: h/a, n/v/d, pneumonia, osteoporosis, hypomagnesemia

contraindications: do not take if lactating, caution in children and pts with respiratory conditions, interacts with digoxin

nursing: usually taken before meals, preferably in the morning, to maximize their effectiveness; do not stop suddenly (rebound acid hypersecretion), monitor electrolytes (magnesium), increase intake of calcium and vitamin D

mucosal protectant

sucralfate

action: serves as a protective barrier over an ulcer; like a bandaid

uses: ulcers; mainly duodenal ulcers

complications: constipation; decreased systemic effects

contraindications: interferes with multiple medications (antibiotics, digoxin, warfarin)

nursing: take on empty stomach, 1 hour before meals, take at bedtime, take away from other meds, seperate by 2 hours, increase fluids, fiber, and activity

antacids

aluminum hydroxide, magnesium hydroxide, calcium carbonate

action: neutralizes gastric acid

uses: peptic ulcer disease, GERD

complications: constipation, diarrhea, fluid retention (HF), toxicity (renal insufficiency)

contraindications: use caution if pt has bowel perforation/obstruction/abd pain

nursing: take separate by 1-2 hours, assess renal function, assess for c/d

education: overuse can cause constipation, diarrhea, and rebound hypersecretion

laxatives

psyllium, docusate sodium, bisacodyl, senns, lactulose

psyllium- bulk forming- diarrhea, promotes defecation; safest long term

docusate sodium- surfactant- constipation, straining; stool softener

bisacodyl and senna- stimulant- colonoscopy prep, constipation r/t opioid use

lactulose- osmotic- excretes ammonia

complications: GI irritation, rectal burning, fluid retention

contraindications: fecal impaction, bowel obstruction, abd pain

nursing: short term use only, increase fiber and fluids, increases mobility, report ongoing constipation, abd pain, and blood and stool

education: can cause dependency if used too often

antidiarrheals

diphenoxylate + atropine, loperamide (imodium), paregoric

action: decrease intestinal motility and increase fluid and sodium absorption

complications: at high doses a pt can experience opioid effects

contraindications: paregoric can not be used with COPD due to respiratory depression

nursing: assess underlying cause, short term use, stay hydrated, monitor electrolytes, avoid overuse

iron preparations

ferrous sulfate

action: helps with RBC development and the oxygen carrying capacity

uses: iron deficiency anemia

complications: GI distress, teeth staining, iron toxicity in children

contraindications: can not use for other anemias, medication interactions, caffeine, food, and diary interfere with absorption

nursing: seperate by couple of hours, H&H levels, increase fiber and fluids, safe storage, med compliance

vitamin B12/cyanocobalamin

vitamin B12, intranasal cyanocobalamin

action: corrects deficiency

uses: vitamin B12 deficiency, megaloblastic anemia

complications: hypokalemia

nursing: monitor potassium, encourage adherence, monitor CBC, monitor for neuro improvements

folic acid

folic acid

action: production of DNA and erythropoiesis

uses: megaloblastic anemia, prevention of neural tube defects, supplement for alcohol use disorder

contraindications: medication interactions with methotrexate and phenytoin

antiemetics

ondansetron, promethazine, scopolamine

serotonin antagonist- ondansetron- blocks serotonin receptors

dopamine antagonist- promethazine- blocks dopamine receptors

anticholinergic- scopolamine- blocks nerve impulses from the inner ear

uses: prevents emesis, tx of n/v, tx of motion sickness

contraindications: h/a, diarrhea, hypotension, dry mouth, urinary retention, constipation, EPS

nursing: EPS can occur, anticholinergics can treat EPS, do not use opioids, stool softeners or laxatives, avoid activities that require alertness, increase fluids and suck on hard candy for scopolamine, admin 1 hour before procedures, if TD apply 4 hours before event