Antidiarrheals and Laxatives Flashcards
What are the classes of antidiarrheals?
Adsorbents
Antimotility
Flora modifiers
What is the mechanism of action and drug effect of adsorbents?
Binds to the causative bacteria/toxin, which is then eliminated through the stool
What are the indications for adsorbents?
Mild diarrhea
What are examples of adsorbents?
Activated charcoal Bismuth subsalicylate (Pepto-Bismol)
What are the nursing implications for bismuth subsalicylate (Pepto-Bismal)?
Linked with Reyes syndrome
What are the adverse effects of adsorbents?
Increased bleeding time Constipation Confusion in elderly Hearing loss, tinnitus Dark stools and tongue
What is the mechanism of action of antimotility (anticholinergics)?
Decrease intestinal muscle tone and peristalsis of GI traact
What is the drug effect of antimotility (anticholinergics)?
Slows movement of fecal matter through GI tract
What are examples of antimotility (anticholinergics)?
Belladonna alkaloids (Donnatal)
What is the mechanism of action and drug effect of antimotility (opiates)?
Decrease bowel motility
Decrease transit time through the bowel, allowing more time for water and electrolytes to be absorbed
Reduces pain by relief of rectal spasms
What are some antimotility (opiates)?
Loperamide (Imodium)
Diphenoxylate/Atropine (Lomotil)
What are the adverse effects of antimotility (opiates)?
Drowsiness, sedation, dizziness, lethargy Respiratory depression Hypotension Nausea, vomiting, constipation Flushing
What is the mechanism of action and drug effect of flora modifiers?
Replenishes “good” GI tract bacteria that are often destroyed by antibiotics
Suppresses growth of diarrhea-causing bacteria
What are some flora modifiers?
L. acidophilius (Lactinex, Bacid) Lactobacillus GG (Culturelle) Bifidus regularis (Dannon Activa yogurt)
What are the nursing implications for antidiarrheals?
Obtain thorough history of bowel patterns, general state of health, history of recent illness, dietary changes, and travel
Assess for contraindications (bowel obstruction, bacterial/parasite infection)
DO NOT give bismuth subsalicylate to children or teenagers with chickenpox/influenza because risk Reye’s syndrome
What are the classes of laxatives?
Bulk-forming laxatives
Surfactant laxatives
Osmotic laxatives
Stimulant laxatives
What is the mechanism of action and drug effect of bulk forming laxatives?
Absorbs water, swelling to a bulky substance that distends the wall of the colon which elicits a defecation reflex
Act in manner similar to naturally occurring dietary fiber
What are some bulk forming laxatives?
Psyllium (Metamucil)
Methylcellulose (Citrucel)
What is the mechanism of action and drug effect of surfactant laxatives?
Allows penetration of water into hardened fecal mass to soften it
DOES NOT promote peristaltic activity
Considered a “stool softener” and not a true laxative
What are examples of surfactant laxatives?
Docusate salts (Colace) Mineral oil (lubricant)
What is the mechanism of action and drug effect of osmotic laxatives?
Increased osmotic pressure draws water from tissues into colon
Bowel distention stimulates stretch receptors of colon which induces peristalsis and evacuation
What are some osmotic laxatives?
Magnesium citrate
Lactulose
Polyethylene glyco (Golytely, Moviprep, Miralax)
What is the mechanism of action and drug effect of stimulant laxatives?
Stimulates peristalsis via direct intestinal nerve stimulation
What are some stimulant laxatives?
Senna (Senekot)
Bisacodyl (Dulcolax)
What are nursing implications for stimulant laxatives?
This laxative class is most likely to cause dependence
What are nursing implications for laxatives?
Obtain thorough history of present symptoms, elimination patters, and allergies
Assess fluid and electrolytes before initiating therapy
Contact physician if experience severe abdominal pain, muscle weakness, cramps, dizziness (possible fluid/electrolyte loss)
Alternative to laxative use: healthy, high-fiber diet and increased fluid intake and activity
Long-term use of laxatives result in decreased bowel tone (dependency)
Take tablets with water
