Laxatives

Question 1

Bulk forming laxatives: psyllium (metamucil)

Answer 1

-Action: absorbs water in intestine -> peristalsis, distends bowel to initiate bowel activity
-use: chronic constipation, FIRST LINE THERAPY

Question 2

Saline laxative: magnesium hydroxide (MOM)

Answer 2

-action: increases osmotic pressure within intestinal tract -> more water in intestines, bowel distention -> peristalsis -> evacuation
-use: generally not recommended except in opioid induced constipation or in preparation for surgical procedures
-rapid results (3-6h)

Question 3

Osmotic laxative: polyethylene glycol (lax a day)

Answer 3

-Action: draws water in intestines by osmosis-> softer stool/ distending bowel/peristalsis
-Use: occasional constipation, recommended if bulk laxatives not efficient

Question 4

Osmotic laxatives: lactulose (cephula)

Answer 4

-Action: same as lax a day
-Use: chronic constipation, reduces serum ammonia levels
-may rise blood glucose levels in diabetic bc base is sugar

Question 5

Lubricant laxatives (mineral oil)

Answer 5

-Action: works in colon, lubricates fecal material and intestinal walls, reduces water absorption (promotes more water/fat in stool)
-Use:acute/chronic, fecal impaction, facilitation of BM in anorectal conditions
-long term risk: fat soluble vitamins malabsorption

Question 6

Surfactant laxatives: docusate sodium (colace)

Answer 6

-Action: facilitates passage of water and fats into fecal -> softens
-Use: prevention of constipation for pt who shouldn’t strain
-if pt has cardiac disease, avoid straining!!!

Question 7

Stimulant laxatives: bisacodyl (ducolax)

Answer 7

-Action: stimulates peristalsis, increases water and electrolytes in intestine, increase peristalsis via intestinal nerve stimulation
-Considerations: may cause electrolyte imbalance, pt can become dependent on it for BM

Question 8

Stimulant laxatives: sennosides (senekot)

Answer 8

-Action: stimulates peristalsis and increases water water an electrolyte in intestine, peristalsis via intestinal nerve
-Use: constipation associated with constipation drugs/neurologic constipation
-may cause electrolyte imbalance, 6-12h

Question 9

Osmotic laxative: glycerin

Answer 9

-Action: increases fecal water content, mild local irritating effect, like other osmotic laxatives
-Use: only short term therapy
-results in 15-60min, suppository

Question 10

Saline laxative: sodium phosphate (fleet enema)

Answer 10

-Action: water retention, peristalsis
-Use: given to clear intestines of feces, to prep for certain diagnostic tests
-usually administered after other laxative therapies failed, 15min, caution if pt on sodium restriction