CH 59+ 60, GI Flashcards
Physiology of Upper Gastrointestinal Tract
- stomach secretes acid, enzymes, and hormones that are essential to digestive physiology
What are the natural defenses of the stomach?
- somatostatin
- bicarbonate ion
- mucus
- prostaglandin E2
What do prostaglandin antagonists include?
- NSAIDs/ASA (damages GI mucosa directly)
- corticosteroids
Peptic ulcer risk factors
- infection w/ H. pylori
- close family hx of PUD
- drugs
- blood group O
- smoking tobacco
- excessive caffeine
- psychological stress (thought to be primary cause of PUD)
what drugs increase risk of peptic ulcer disease (PUD?)
- glucorticoids
- NSAIDs
- platelet inhibitors
PUD: NSAID-induced risk factors
- long-term use
- advanced age
- hx of ulcers
- corticosteroids
- anticoagulants
- alcohol + smoking
Goals of PUD pharmacotherapy
- relieve symptoms
- promote healing
- prevent complications
- prevent future recurrence
what do PPIs end in? and what do they do?
“-prazole”
- PPIs block gastric acid secretion
- choice of drug therapy in PUD + gastroesophageal reflex disease
H2 -receptor antagonists - what do they do?
suppress gastric acid secretion & are widely prescribed for treating PUD + gastroesophageal disease
what are the H2-receptor antagonists?
- ranitidine (Zantac)
- cimetidine (Tagamet)
- famotidine (pepcid)
- nizatidine (axid)
H2 receptor antagonists - Pharmacokinetic properties
- rapid absorption from SI
- 30 minute onset of action
- half-life from 1-4h
- no known effects on fetus
- excreted primarily from kidneys
what are antacids?
= alkaline substancse that neutralize stomach acid to treat symptoms of heartburn
Antacids Pharmacotherapy: AEs
- constipation
- @ high doses, aluminum products bind w/ phosphate in GI tract = LT use can result in phosphate depletion
- high risk in: malnourished, alcoholics, renal disease
Symptoms of bowel obstruction
abdominal distension, n/v, bloating, tender
SNT - soft, non-tender, no distention?
Antacids: Contraindications / precautions
- prolonged use with low serum phosphate
- avoid w/ suspected bowel obstruction
Antacids: Drug Interactions
- don’t take with other meds – will interfere w/ absorption
- anticholinergic drugs incr effects of antacids
- aluminum + calcium antacids may inhbit absorption of dietary iron
- decr absorption of some drugs
Antacids decrease the absorption of which drugs?
- cimetidine
- fluoroquinolones
- digoxin
- isoniazid
- chloroquine
- NSAIDs
- iron salts
- phenytoin
- tetracycline
- thyroxine
Considerations w/ Antacids
- PMH
- watch kidney labratory values
- monitor for bowel changes & worsening symptoms
- **hold drug + notify prescriber **if pt has symptoms of appendicitis, undiagnosed GI bleeding, or suspected obstruction
What helps with simple nausea, such as motion sickness?
Pharmacotherapy of N/V
- anticholinergic agents (scopolamine)
- antihistamines (dimenhydrinate/diphenhydramine)
What helps with chemotherapy-induced N/V?
Pharmacotherapy of N/V
- serotonin (5-HT3) receptor antagonists (Zofran)
what is the primary indication for the use of antiemetic medication?
chemotherapy-induced nausea and vomiting
what is used for antineoplastic therapy?
Pharmacotherapy of N/V
- phenothiazine (methotrimeprazine / Nozinan)
- hydroxyzine (Atarax)
- dopamine antagonists –> Metoclopramide (Reglan)
Ondansetron - Therapeutic + Pharmacological classification?
therapeutic: antiemetic
pharmacologic: serotonin (5-HT3) receptor antagonist
Therapeutic use of ondansetron/ Zofran?
- treatment of serious N/V
- used at least 30 min prior to chemotherapy + continued for several days after
- off-label use for cholestatic or opioid-induced pruritus
Ondansetron mechanism of action?
- blocks serotonin receptors in chemoreceptor trigger zone
What does Saline Cathartic do?
Pharmacotherapy w/ Laxatives
pulls water into stool (sennosides)
- implies accelerated, stronger, and more complete bowel empyting through osmosis
What do laxatives do (bulk forming)?
Pharmacotherapy w/ Laxatives
- promotes defecation
- prevents and treats constipation
- Metamucil + surfactnat type (docusate sodium)
What to monitor with laxatives?
monitor for retrosternal pain (bulking from behind) + possible bowel perforation
Treatment with laxatives?
Pharmacotherapy w/ Laxatives
- simple, chroni constipation
- accelerate removal of ingested toxic substances
- accelerate removal of dead parasites
- cleanse bowel prior to diagnostic or surgical procedures
Metamucil considerations
Pharmacotherapy w/ Laxatives
- know PMHx
- assess BMs + GI functioning
- mix power + granules w/ at least 8 ounces of pleasant-tasting liquid immediately before use, drinks lots of h2o
- immediately report complaints of retrosternal pain after taking drug to prescriber
- smaller, more frequent doses spaced throughout day to relieve discomfort
- monitor warfarin + digoxin levels closely
Most common opioids for diarrhea + why?
Pharmacotherapy of Diarrhea
- opioids = most effective for controlling severe diarrhea
- common opioids: codeine + diphenoxylate with atropine (Lomotil)
Diphenoxylate w/ Atropine (Lomotil): therapeutic + pharmacologic classification
Pharmacotherapy of Diarrhea
- antidiarrheal
- P = opioid
diphenoxylate with atropine (Lomotil): therapeutic effects + uses
- moderate to severe diarrhea
- not recommended for infants
- low-maintenance dose can by continued for up to 10 days
- approved for children 2yr+
diphenoxylate with atropine (Lomotil): mechanism of action
acts on smooth muscle cells of intestine to slow peristalsis
diphenoxylate with atropine (Lomotil): Adverse effects
- dizziness
- lethargy, drowsiness,
- anticholinergic effects of atropine
diphenoxylate with atropine (Lomotil): Considerations
- know PMHx + Sx
- complete assessment of BM + GI function (freq + consistency of stools)
- report abdo distension + s/s decr peristalsis
- want to find SNTnoD –> softness, non-tender, no distension
- monitor s/s dehyration, esp young children
- maintain safe env’t bc can cause drowsiness/dizziness
what is used to treat IBD?
Pharmacotherapy of IBD
- 5-ASA agents
- immunosuppressants
- biologic therapies
- anti-inflammatory drugs
Goals of IBD pharmacotherapy?
- reduce symptoms
- keep in remission (immunosuppressive agents)
- alter progression of disease
What is used for induction therapy with Crohn’s Disease?
- 5-aminosalicylic acid (5-ASA) agents
- sulfasalazine, olsalazine, balsalazide, mesalamine
severe: corticosteroids
maintenance: immunosuppresive agents
Sulfasalazine + Sulfonamides
Sulfonamide is basis of what groups of drugs?
IBD Pharmacotherapy
- sulfonylureas
- sulfonamide antibiotics
- loop + thiazide diuretics
Contraindications / Precautions with Suflasalazine
- sulfonamide / salicylate hypersensitivity
- urinary obstruction
- can worsen blood dyscrasias
- hepatic impairment
- dehydration
- diabetes/ hypoglycemia
