Drugs for Constipation: laxatives

Question 1

normal BM

Answer 1

• formed
• w/o straining
• sense of completeness

Question 2

causes of constipation

Answer 2

• medication = opioids, aluminum based antacids
• aging process
• poor fluid or fiber intake

Question 3

indications for laxatives

Answer 3

1. to treat constipation = pregnant women, elderly, paraplegic
2. to prevent straining = cardiac pts, vaso vagal response
3. bowel prep for procedures
4. prevent ammonia absorption = pts w/ESLD

Question 4

contraindications for laxatives

Answer 4

1. pts w/undiagnosed abdominal pain
2. pts w/acute surgical abdomen
3. pts w/fecal impaction or obstruction

Should not be used habitually
OTC drugs may decrease effectiveness of laxatives

Question 5

bulk-forming laxatives

Answer 5

• absorb water into stool - ⇡mass and water contents of stool, promoting evacuation
• effective in 2-3 days
• acts like dietary fiber

pslyllium (Metamucil) - mix w/liquid before administration

SE: abdominal distension

Question 6

surfactant laxatives

Answer 6

• stool softener
• ⇡ water and fat absorption into stool –> stools are softer / prevents straining
• effective in 1-3 days, taken daily
• good for cardiac patients

docusate sodium (Colace)
docusate calcium (Surfak)

SE: diarrhea

Question 7

osmotic laxatives

Answer 7

• ⇡ osmotic pressure in colon - cause water to be retained - semifluid stool

Contraindicated: pts w/renal impairment or ESRD
SE: ⇡ Mg level; dehydration

magnesium hydroxide (MOM)
magnesium citrate
== rapid results

Question 8

stimulant laxatives

Answer 8

• stimulate peristolsis
• widely used and abused by public

bisacodyl (Dulcolax)
fleet enema
Castor oil
senna (Senokot)

SE: diarrhea, abdominal cramping

Question 9

GoLYTELY

Answer 9

bowel cleansing solution before diagnostic procedure

(4 L)

Question 10

Lactulose

Answer 10

• pulls water into intestine lumen
• treats constipation
• used to treat hepatic encephalopathy in pts w/ESLD (S/Sx - asterixis (aka liver flap) - extended palms “flap” - caused by ⇡ of ammonia b/c liver can’t rid body of toxins)

SE: abdominal cramping, diarrhea

Question 11

NI and Pt Ed. for laxatives

Answer 11

• Safest: Metamucil
• never recommend using in pt w/undiagnosed abdominal pain
• do not use >7 days
• if no BM for several days, check for fecal impaction before laxative admin

Pt ed: eat fiber, ⇡ fluids, exercise