Laxatives

Question 1

causes of constipation

Answer 1

1. Insufficient consumption of fiber and/or water
2. Lack of exercise/activity, pregnancy
3. DRUGS that cause constipation: anticholinergics, opioids (anesthesia), antacids, iron, ETOH, chronic laxative use
4. Ignoring the urge to defecate (impaction)
5. Bowel obstruction (intussusception, volvulus)
6. History of abdominal surgeries (scar formation)
7. Neurologic disorders (paraplegia)
8. Hypothyroidism, diabetes, irritable bowel syndrome (IBS)

Question 2

laxative indications

Answer 2

1. therapeutic/prophylactic treatments for constipation associated with
   a) Opioid use
   b) Pregnancy
   c) Prevent painful BM with hemorrhoid or post episiotomy
   d) Prevent straining (with aneurysm, myocardial infarction)
   e) Evacuation of bowel (prep for colonoscopy, post-ingestion of poisons)

Question 3

laxative contraindications

Answer 3

1. with other enteral medication (separate at least for 2 hours)
2. abdominal pain/cramping (need to know if it is caused by an obstruction!), nausea, vomiting
   a) fecal impaction, bowel obstruction, ischemic bowel
   b) biliary obstruction, appendicitis, diverticulitis, GI bleed

Question 4

osmotic laxatives hyperosmolar saline drugs w/ routes (4)

Answer 4

1. polyethylene glycol [PEG] 
= PO drink 
= Contraindication: using > 1 week
2. PEG w/ electrolytes 
= PO drink
3. magnesium hydroxide:
= PO drink, also antacid
4. saline enema

Question 5

osmotic laxatives hyperosmolar saline contraindication

Answer 5

• RF
• children < 2
• –> requires renal function to excrete excess electrolytes

Question 6

osmotic laxatives hyperosmolar saline nursing

Answer 6

• monitor for abnormally high level of electrolytes (magnesium!)
• monitor VS trends of low BP w/ tachycardia

Question 7

osmotic laxatives hyperosmolar saline side effects

Answer 7

• hypermagnesemia = cardiac arrest

- hypovolemia

Question 8

osmotic laxatives hyperosmolar saline indication

Answer 8

it is a quick treatment, result within 2 hours

- used for colonoscopy preparation

Question 9

stimulant (irritants) drugs (4)

Answer 9

1. bisacodyl OTC; PO, PR
2. senna OTC; PO
3. castor oil OTC; PO
4. soapsuds enema

Question 10

bisacodyl and senna MOA

Answer 10

increase peristalsis by irritating sensory nerve endings in intestinal mucosa

Question 11

bisacodyl and senna indication

Answer 11

quick treatment

• PO: 6-12 hours
• PR: 15-60 min

Question 12

bisacodyl and senna contraindication with PO form

Answer 12

avoid milk or antacid, at least 1 hour apart

Question 13

bisacodyl and senna side effects

Answer 13

1. anorexia
2. N/V, cramps
3. weakness
4. reddish brown urine
5. dependence
6. suppository only:
   
   • proctitis: inflammation of the rectum and anus, burning sensation

Question 14

soapsuds enema MOA/indication

Answer 14

• castile is a mild soap
• Used when other medications are not effective
  MOA:
• the suds irritate the bowels increasing the peristalsis
• the soap also works as an emollient
• the large volume water increases the water in stool

Question 15

emollient (stool softeners) drugs (3)

Answer 15

1. docusate sodium
2. docusate sodium / senna (stimulating peristalsis w/ senna and using the emollient docusate)
3. mineral oil enema

Question 16

emollient (stool softeners) MOA (3) and duration

Answer 16

1. Lowers surface tension (works like surfactant)
2. Promotes water penetration in the stool
3. Emulsifies and lubricates feces for easier passage

Maintenance: results are slow acting

Question 17

bulk-forming drugs

Answer 17

psyllium

Question 18

psyllium MOA

Answer 18

1. Natural fibers (nonabsorbable) made from psyllium plant seed
   a) Identical to the action of dietary fiber
   b) Increase fecal bulk & soften fecal mass

Question 19

psyllium nursing

Answer 19

• drink plenty of water to prevent bowel obstruction
• No dependence!
• Maintenance: results in 8-24 hours