42. GI Meds Flashcards
3 physiologic causes of vomiting
- activation of chemoreceptor trigger zone CTZ (pregnancy) -> triggered by dopamine
- inner ear receptors (motion sickness)
- vomiting center in medulla in stimulated -> triggered by dopamine
most common adverse effect of drug therapy
N/V
non pharmacological techniques for N/V
- herbal supplements
- acupuncture and acupressure
- flat soda/white soda
- weak tea
- ginger
nonprescription drugs for N/V
- antihistamine antiemetics: meclisine and diphenhydramine for N/V and dizziness
- bismuth subsalicylate (peptobismol) acts on gastric mucosa to suppress vomiting
what type of drug is promethazine
phenothiazine or antihistamine
MOA of promethazine
blocks dopamine from H1 receptor sites in brain and inhibits CTZ (works better for prevention than to actually prevent vomiting)
uses for promethazine
- motion sickness
- nausea
- sedation induction
adverse effects of promethazine
- EPS
- blurred vision
- urinary retention
- dry mouth
- photosensitivity
- drowsiness
- confusion
- agranulocytosis
- leukopenia
- respiratory depression
black box warning for promethazine
- can cause fatal respiratory depression in children under 2 y/o
cautions for promethazine
- contraindicated for subQ infection, avoid IV if available (irritating to skin)
- more commonly given IM
- use caution in pt’s w/ liver disease
describe 2 type of histamines
- H1 receptor blockers are classic antihistamines used to as antiemetics
- H2 receptor blockers such as cimetidine
what type of drug is hydroxyzine
antihistamine
MOA of hydroxyzine
competes w/ histamine for receptor sites in GI tract, blood vessels, and respiratory tract
uses of hydroxyzine
- N/V
- motion sickness
- seasonal allergies
- anxiety
- anesthesia
- vertigo
adverse effects of hydroxyzine
anticholinergic effects such as
- drowsy/dizzy
- confusion
- dry mouth
- thickened respiratory secretions
- blurred vision
- urinary retention
- tachycardia
T/F: hydroxyzine is not appropriate to give older adults due to the sedating effects
True
what type of drug is ondansetron
5-HT3 receptor antagonist
MOA of ondansetron
serotonin antagonist suppresses N/V by blocking serotonin (5HT3) receptors in the CTZ and blocking afferent vagal nerve terminals in upper GI tract
uses of ondansetron
moderate to severe N/V particularly in chemo, radiation, and post-op
adverse effects of ondansetron
- diarrhea
- headache
- dizziness
- constipation
- fatigue
- transient elevation of liver enzymes
- pain at injection site
administration
- can be given IV
- PO (SL)
what type of drug is scopolamine
anticholinergic
MOA of scopolamine
inhibits action of ACh at muscarinic receptors
uses of scopolamine
motion sickness and IBS
adverse effects of scopolamine
- urinary retention
- constipation
- dry mouth
- fatigue
- dizziness
- drowsiness
administration of scopolamine
- PO
- transdermal (apply patch behind ear and switch ears if using longer than 3 days
when are emetics used
if patient has consumed toxic substance
when should emetics not be used
- if caustic substances such as ammonia, chlorine, lye, toilet cleaners, or battery acid have been ingested
- if petroleum distillates are ingested including gasoline, kerosine, paint thinners, and lighter fluid
- activated charcoal is given when emesis is contraindicated
nursing interventions for antiemetics
- assess pt’s condition and report to HCP if N/V occur
- suggest pregnant women eat dry crackers before rising in morning and ingestion of small frequent protein meals to help prevent N/V
- avoid administering oral intake food, fluids, and drugs during acute episodes of N/V
- minimize activity during N/V (lying down and resting are often helpful)
- help pt rinse mouth after vomiting (decrease bad taste and corrosion of tooth enamel)
- provide requested home remedies when possible (cold wash cloth on face)
- provide education for drug therapy
when to administer antiemetics
- 30-60 minutes before a nausea producing event when possible
- adjust the timing of any oral drugs that cause gastric irritation, N/V by taking w/ or just before food
what foods to resume eating after N/V
- BRAT diet (bananas, rice, applesauce, and toast)
- foods not spicy or fatty
characteristics of diarrhea
- acute or chronic; mild or severe
- most episodes are the body trying to rid itself of irritants, toxins, and infectious agents
- usually self-limiting 24-48 hours
- severe or prolonged may lead to fluid and electrolyte depletion
- chronic diarrhea can have exacerbations and remissions
nonpharmacologic interventions for diarrhea
- increase clear liquids (gatorade or pedialyte)
- may need IV fluids
what type of drug is diphenoxylate w/ atropine
opioid antidiarrheal agent (schedule 4)
MOA of diphenoxylate w/ atropine
inhibits gastric motility by exerting effect on smooth muscle cells of GI tract
uses of diphenoxylate w/ atropine
- treats diarrhea by slowing intestinal motility
- not given if diarrhea caused by infectious agents)
adverse effects of diphenoxylate w/ atropine
- paralytic ileus
- toxic megacolon
- anaphylaxis
- pancreatitis
- tachycardia
- drowsy/dizzy
- confusion and restless
- flushing
- rash
what type of drug is bismuth subsalicylate
absorbent
MOA of bismuth subsalicylate
coating the wall of the GI tract and absorbing bacteria or toxins that cause diarrhea
uses of bismuth subsalicylate
travelers diarrhea and can be used as an antacid for gastric comfort
adverse effects of bismuth subsalicylate
- dizzy/drowsy
- weakness
- anxiety
- confusion
- tinnitus
- tongue discoloration
- stool discoloration
contraindication for bismuth subsalicylate
- people w/ allergy to ASA
what is the medical definition of constipation
3 or fewer bowel movements per week
nonpharmacologic interventions for constipation
- increase activity and exercise
- increase dietary intake of fiber
- drink at least 2000mL of fluid per day (if not contraindicated)
- establish and maintain routine for bowel elimination
what type of drug is lactulose
osmotic
MOA of lactulose
- draws water into intestines to form a soft stool
- decreases serum ammonia levels
use of lactulose
constipation and hepatic encephalopathy
adverse effects of lactulose
- belching
- flatulence
- N/V/D
- ABD pain
- metabolic acidosis
- hypokalemia
- hypernatremia
what type of drug is bisacodyl
stimulant
MOA of bisacodyl
increase peristalsis by direct effect on smooth muscle of intestine
use of bisacodyl
- bowel prep
- prevention and short-term treatment of constipation
- over the counter
adverse effects of bisacodyl
- dependence
- fluid and electrolyte imbalance
- dizziness
- anorexia
- N/V
- rectal burning and diarrhea
contraindications of bisacodyl
- fecal impaction
- intestinal obstruction
- GI bleeding
- appendicitis
what type of drug is docusate sodium
emollient: stool softener
MOA of docusate sodium
decrease surface tension by mixing liquid w/ bowel contents
use of docusate sodium
constipation or prevent constipation (postpartum or while taking opioids)
side effects of docusate sodium
- throat irritation
- diarrhea
- ABD cramps
contraindications for docusate sodium
- pregnancy
- inflammatory disorders of GI tract
what type of drug is psyllium
bulk-forming
MOA of psyllium
acts as a bulk-forming laxative by drawing water into intestines (acts like fiber)
use of psyllium
- to control constipation
- to reduce serum cholesterol levels (fiber prevents absorption of cholesterol)
adverse effects of psyllium
- ABD cramping
- diarrhea
- flatulence
- esophageal or intestinal obstruction
- bronchospasm
- anaphylaxis
