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.