laxatives Flashcards
What are the purposes of laxatives?
Laxatives ease or stimulate defecation, soften stool, increase stool volume, hasten fecal passage, and facilitate evacuation.
What is the difference between laxative effect and cathartic effect?
Laxative effect produces soft, formed stool over 1+ days; cathartic effect causes prompt, fluid evacuation of the bowel.
When are laxatives used?
Laxatives are used for constipation, colonoscopy prep, stool samples, bowel emptying, fecal impaction prevention, and to remove poisons.
What are the contraindications for laxatives?
Abdominal pain, nausea, cramps, acute surgical abdomen, fecal impaction, habitual use, caution in pregnancy/lactation.
What are bulk-forming laxatives?
Bulk-forming laxatives, like psyllium and methylcellulose, are the safest and act as dietary fiber to soften stool and increase bulk.
What are the side effects of bulk-forming laxatives?
May cause obstruction if not taken with adequate water.
What is the action of surfactant laxatives (e.g., Docusate sodium/Colace)?
Surfactant laxatives lower stool surface tension, allowing more water penetration to soften the stool.
What is the recommended use for Docusate sodium?
Take with 8 oz of water, and it softens stool in 1–3 days.
What are stimulant laxatives?
Stimulant laxatives, like bisacodyl, senna, and castor oil, stimulate intestinal motility and increase water/electrolyte volume.
What are the side effects of bisacodyl?
Oral bisacodyl works in 6-12 hours; rectal bisacodyl works in 15-60 minutes; it may cause burning or proctitis.
What are the side effects of senna?
Senna may cause harmless yellow-brown or pink urine discoloration.
What are the side effects of castor oil?
Castor oil has an unpleasant taste and can take 2-6 hours to work. It should be mixed with fruit juice.
What are osmotic laxatives (laxative salts)?
Osmotic laxatives, like magnesium hydroxide, citrate, sulfate, and sodium phosphate, draw water into the intestines to increase stool mass.
What are the side effects of osmotic laxatives?
High doses may cause bowel prep, toxic magnesium levels, sodium absorption, fluid retention, and dehydration.
What is polyethylene glycol (Miralax)?
Polyethylene glycol is a safe osmotic laxative that works in 2–3 days with mild side effects like nausea, bloating, and cramping.
What is lactulose used for?
Lactulose enhances stool excretion and lowers blood ammonia, used in portal HTN and hepatic encephalopathy.
What are the side effects of lactulose?
Lactulose may cause flatulence and cramping.
What is the purpose of mineral oil as a laxative?
Mineral oil acts as a lubricant and is useful as an enema in fecal impaction.
What are the side effects of mineral oil?
Mineral oil can cause lipid pneumonia, anal leakage, and liver issues if used orally.
What is the use of glycerin suppositories?
Glycerin suppositories soften and lubricate impacted feces, commonly used for constipation in children.
How long does glycerin suppository take to work?
Glycerin suppository works in 30 minutes for constipation and 1 hour for bowel prep.
What are the side effects of glycerin suppositories?
Glycerin suppositories may stimulate rectal contraction
What is sodium phosphate used for in laxatives?
Sodium phosphate is a hypertonic laxative used for bowel prep but can cause dehydration and electrolyte disturbances.
What are the side effects of sodium phosphate?
Sodium phosphate can lead to dehydration, electrolyte disturbances, and renal damage.
