Week 6: Antidiarrheals and Laxatives Flashcards by Kristin Heins (2024)

• antimotility agent that inhibits excessive GI motility and GI propulsion
• atropine has anticholinergic effects that decrease secretion in the bowel and slow peristalsis

• antimotility agent that acts through opiod receptors to inhibit peristalsis and prolong gastric time
• also reduces fecal volume and diminishes loss of fluid and electrolytes

exhibits both antisecretory and antimicrobial actions

• prevent secretions from entering the GI tract

• Schedule V controlled substance
• contraindicated in glaucoma, BPH and those with bacterial entercolitis (anticolinergic)
• use cautiously in the elderly and in pregnancy

• black stools, darkening of tongue
• avoid in pts w/ ASA allergy or those taking salicylates
• avoid in pregnancy, lactation, and in pediatrics

• risk of rebound constipation - need to increase fluid intake and electrolyte drink if PO intake is poor

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)

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

• 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

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

• use caustion with narrowed esophageal or intestinal lumen
• OK with pregnancy/lactations
• OK in pediatrics > 6 y/o

• abdominal cramping, bloating, esophageal or intestinal obstruction (rare), gas

Osmotic 2nd line treatment of constipation

• draws water into the intestinal lumen to increase intraluminal pressure, which distends the colon and increases peristalsis

• use lactulose with caution in diabetics
• use magnesium-based with caution in renal impairment

stool softener

• reduces the surface tension of the oil-water interface on the stool and facilitates admixture of fat and water into the stool, producing an emollient action

Lubricant 2nd line treatment of constipation

• eases passage of stool by decreasing water absorption and lubricating the intestine

• avoid in pregnancy/lactation
• avoid in the elderly
• ok for pediatrics > 6 y/o

• abdominal cramping, diarrhea, nausea, oily rectal leakage, vomiting

Injection used for opiod induced constipation, IBS in women >18 y/o

• chronic idiopathic constipation

Chloride channel activator/hyperosmotic

• activate chloride channels in the GI epithelial lining, producing chloride-rich secretions that soften the stool and increase motility - pulls a large amount of water into the GI tract

• known or suspected bowel obstruction
• not recommended in pregnancy or pediatrics

• headache, nausea, diarrhea, abdominal pain and bloating
• can change blood pressure

Pamora - peripheral acting mu opiod receptor antagonist

Think Methylanaltrexone / Naloxone

opiod receptor antagonist at the mu receptors in the GI tract - acts only in the peripheral nervous system so opiods still can work in the CNS

opiod-induced constipation (OIC)

• better option to Amitiza

• known or suspected bowel obstruction
• use caution in pregnancy
• not recommended in pediatrics
• monitor for opiod withdrawal symptoms - displacing opiod on the opiod receptors in the periphery - not in the CNS

• flatulence, nausea, diarrhea, abdominal pain and bloating