Week 6: Antidiarrheals and Laxatives Flashcards
Diphenoxylate/Atropine (Lomotil) MOA
- antimotility agent that inhibits excessive GI motility and GI propulsion
- atropine is added to this and has anticholinergic effects that decrease secretion in the bowel and slow peristalsis
Loperamide (Imodium) MOA
- antimotility agent that acts through opiod receptors to inhibit peristalsis and prolong gastric time
- reduces fecal volume and diminishes loss of fluid and electrolytes
Bismuth Subsalicylate (Pepto Bismol) MOA
both antisecretory and antimicrobial actions
- prevent secretions from entering the GI tract
Kaolin and Pectin (Kaopectate) MOA
a clay-like powder that attracts and hold bacteria, and pectin thickens the stool by absorbing mosture
Polycarbophil (FiberCon) MOA
can provide bulk to your stools by absorbing water in the GI tract
diphenoxylate/atropine (Lomotil) ADRs
anticholinergic effects!
Dry mouth, dry eyes, urinary retention, blurred visions, drowsiness, dizziness, confusion/sedation
Lomotil cautions/contraindications
- Schedule V - risk of dependence!
- caution in liver dz, fever, bloody stool, fecal leukocytes
loperamide (Imodium) ADRs
abdominal discomfort, constipation, drowsiness, dry mouth
Bismuth (Pepto Bismol) ADRs
- black stools, darkening of tongue, tinnitus
- avoid in pts w/ ASA allergy or those taking salicylates
- avoid in pregnancy, lactation, and in pediatrics (has aspirin = reyes syndrome)
Antidiarrheal patient education
- risk of rebound constipation
- need to increase fluid intake and electrolyte drink if PO intake is poor
Laxitives
1st line for maintenance:
- Bulk Laxatives: Methylcellulose (Citrucel) and Psyllium (Metamucil)
- Stool Softeners: (Colace)
2nd line
- Lubricant Laxatives: Glycerin suppositories and Mineral oil
3rd line (or 1st line for acute constipation)
-Irritants and Stimulants: Bisacodyl (Correctol, Dulcolax), Caster oil, Senna (Ex-lax, Senokot)
Senna (Senokot), bisacodyl (Dulcolax), caster oil MOA
Stimulant 3rd line treatment in chronic constipation (or 1st line in acute constipation)
- directly stimulates the myenteric plexus, which results in prostaglandin release and increase in cAMP concentration
- dramatically increases peristaltic activity
Senna/Stimulant ADRs
Abdominal cramping, electrolyte imbalance, diarrhea, nausea, vomiting
- loose stools with prolonged use
Stimulants (Senna/Bisacodyl) cautions/ contraindications
- caution in CV disease
- not to be used if bowel obstruction is suspected or active
- safe in pregnancy and lactation (except caster oil)
- bisacodyl ok in pediatrics > 6 y/o
- senna and caster oil ok in pediatrics > 2 y/o
- no caster oil in preg/lac
Psyllium (Metamucil) MOA
Bulk Laxative that is the safest 1st line drug for constipation
- absorbs water in the intestine to form a viscous liquid that promotes peristalsis and reduces transit time
Psyllium (Metamucil) Cautions/ contraindications
- use caution with narrowed esophageal or intestinal lumen
- undx abd pain/bowel obstruction
- OK with pregnancy/lactations
- OK in pediatrics > 6 y/o
Psyllium (Metamucil) ADRs
- abdominal cramping, bloating, esophageal or intestinal obstruction (rare), gas
Magnesium Hydroxide (Milk of Mag) and Polyethylene glycol (Miralax) and Lactulose MOA
Osmotic 2nd line treatment of constipation
- draws water into the intestinal lumen to increase intraluminal pressure, which distends the colon and increases peristalsis
Osmotics ADRs
abdominal cramping, nausea, diarrhea, bloating
Osmotics Cautions/contraindications
- lactulose with caution in diabetics
- use magnesium-based with caution in renal impairment
Docusate sodium (Colace) MOA
stool softener
- reduces the surface tension of the oil/water interface on the stool and facilitates a mixture of fat and water into the stool
- emollient action
Mineral oil/glycerin MOA
Lubricant 2nd line treatment of constipation
- eases passage of stool by decreasing water absorption and lubricating the intestine
Lubricants cautions/contraindications
- avoid in pregnancy/lactation
- avoid in the elderly / BEERS
- ok for pediatrics > 6 y/o
Lubricants/Mineral oil ADRs
- abdominal cramping, diarrhea, nausea, oily rectal leakage, vomiting
Chloride Channel Activators: Lubiprosone (Amitiza) Indications
Injection used for opioid induced constipation, IBS in women >18 y/o
- chronic idiopathic constipation
Lubiprosone (Amitiza) MOA
Chloride channel activator/hyperosmotic
- activate chloride channels in the GI epithelial lining, producing chloride-rich secretions that soften the stool and increase motility
Lubiprosone (Amitiza) cautions/ contraindicaitons
- NO if known or suspected bowel obstruction
- NO in pregnancy or pediatrics
Lubiprosone (amitiza) ADRs
- headache, nausea, diarrhea, abdominal pain and bloating
Opiod-Receptor Antagonist - Methylnaltrexone (Relistor) MOA
Think Methylanaltrexone / Naloxone
opioid receptor antagonist at the mu receptors in the GI tract -
Methylnaltrexone (Relistor) indications
opiod-induced constipation (OIC)
- better option to Amitiza
Opiod-receptor antagonists (Relistor) cautions/ contraindications
- known or suspected bowel obstruction
- use caution in pregnancy
- not recommended in pediatrics
- monitor for opiod withdrawal symptoms
Relistor ADRs
- flatulence, nausea, diarrhea, abdominal pain and bloating
- opioid withdrawal
