pharmacology - chapter 31 - types of laxatives
opioid antagonists
binds to opioid receptors in GI tract, inhibiting constipation effects of opioid drugs, does not cross blood-brain barrier, does not affect analgesic effects of opioids
stool softeners example
docusate sodium (colace)
categories of antidiarrheals
local and systemic
lubricant laxative
lubricates intestinal wall and softens stool. does not cause significant bowel spasms, oil can be aspirated into lungs and cause lipid pneumonia
saline laxative examples
magnesium hydroxide (milk of mag.), magnesium sulfate, magnesium citrate (citrate of mag.), sodium phosphates (fleets soda)
stool softeners
may require up to 72 hrs to take effect, used frequently after surgery to prevent straining
opioid antagonists examples
methylnaltrexone (relistor), naloxegol (movantik)
lubricant laxative examples
mineral oil
antidiarrheal
should not be used to treat diarrhea related to bacterial infections. body needs to eliminate bacteria from body
types of laxatives
stimulant laxatives osmotic laxatives saline laxatives lubricant laxatives bulk forming laxatives stool softeners opioid antagonist
bulk forming laxative examples
wheat bran, polycarbophil (fiber con), psyllium (metamucil)
stimulant laxatives
causes irritation that promotes peristalsis and evacuation. they usually work within 6 to 10 hrs orally and 60 to 90 minutes rectally
local antidiarrheal examples
difenoxin with atropine (motofen), diphenosylate with atropine (lomotil), loperamide (immodium A-D), opium (paregoric)
saline laxatives
draws water into intestines from surrounding tissues, accumulated water affects stool consistency and distends bowel, causing peristalsis. usually acts within 1 to 3 hrs. increases intestinal fluid secretion which increases intestinal motility causing passage of feces
osmotic laxatives
draws water into the intestines from surrounding tissues, GoLytely is often used as a colon prep for colonscopy and barium studies
systemic antidiarrheal examples
lactobacillus (lactinex), bismuth subsalicylate (pepto-bismol, kaopectate)
osmotic laxative examples
lactulose, sorbitol, polyethylene glycol (glylytley or colyte), glycerin (glycerin suppositories)
adverse effects of antidiarrheal
abdominal distention, nausea, constipation, prolonged or worsening diarrhea
common adverse effects of laxatives
abdominal spasms, abdominal discomfort with flatulence, nausea, abdominal tenderness, pain, bleeding, vomiting, diarrhea
stimulant laxative examples
bisacodyl (correctol, dulcolax), sennosides A & B (ex-lax, peri-colace, senokot)
bulk forming laxatives
considered the safest laxative, onset of action 12 to 24 hrs, but may take as long as 72 hrs.