Laxatives and Antidiarrheals

Question 1

Bulk-Forming Laxatives

Examples
Action
Contraindication
SE

Answer 1

Methylcellulose, Psyllium, Polycarbophil, Wheat Dextrin

Action:

• Contain hydrophilic elements that draw water into the stools
• Adds Bulk to Stool
• More Bulk in stools stimulates peristalsis
• Helps stools transition through bowels

Contraindications: Intestinal Obstruction

SE: Flatulence, Abdominal Distension, Rarely GI obstruction

** also used as an antidirrheal **

Question 2

** Peripherally Acting Mu-opioid Receptor Antagonist (PAMORA) **

Examples
Action
Indication
Contraindication
SE

Answer 2

Alvimopan, Methylnaltrexone, Naldemedine, Naloxegol

Action:

• Acts as antagonist of opioid binding at the mu-opioid receptors in the gut
• DOES NOT EFFECT CNS

Indication: Opioid-induced constipation in patients with chronic non-cancer pain

Contraindication:

• GI obstruction or increased risk of GI obstruction due to the potential for GI perforation
• Conditions associated with localized or diffuse reduction in the structural integrity of the GI tract wall (PUD, Diverticular Dx, Infiltrative GI Tract Malignancies, Peritoneal Metastases)

SE: abdominal pain, diarrhea, nausea, flatulence, vomiting, headache, hyperhidrosis

Question 3

Key Clinical Considerations (5)

Answer 3

• Certain SE are common to all
  » nausea, diarrhea, abdominal pain, abdominal distention, flatulence
• Avoid in appendicitis, acute surgical abdomen, fecal impaction, intestinal obstruction
• No good evidence that docusate is effective for preventing constipation
• Dispel myth that stimulants cause dependence
• Glycerin is safe and is often used in infants and children