65. Constipation & Diarrhea

Question 1

A 55 year-old male has diarrhea and asks the pharmacist if Pepto-Bismol is safe for him to take. His medications include metoprolol, digoxin, amiodarone and warfarin. Pepto-Bismol is not recommended for use in this patient due to the following concern:

A. Increased risk of arrhythmia
B. Increased risk of bradycardia
C. Increased risk of digoxin toxicity
D. Increased risk of bleeding
E. Increased risk of heart block

Answer 1

D. Salicylates (including bismuth subsalicylate) increase the risk of bleeding.

Question 2

A female patient was using Ex-Lax for constipation, but complained of cramping. The physician has recommended polyethylene glycol (PEG). Choose the correct statement concerning this recommendation:

A. A trade name for polyethylene glycol is Carboplatin.
B. An OTC version is called Dulcolax.
C. GoLytely and MoviPrep contain PEG.
D. PEG is characterized as a stimulant laxative.
E. PEG is characterized as a fiber laxative.

Answer 2

C. There are many prescription formulations used for chronic constipation and for bowel cleansing prior to GI procedures.

Question 3

A patient with constipation presents with a new prescription for Relistor 8 mcg by subcutaneous injection every other day. Which of the following is an appropriate generic substitution for Relistor?

A. Calcium polycarbophil
B. Lubiprostone
C. Docusate
D. Methylnaltrexone
E. Polyethylene glycol

Answer 3

D. The generic name of Relistor is methylnaltrexone.

Question 4

Mirna is a 52 year-old Hispanic female with renal insufficiency due to IgA nephropathy, hypertension, anemia, dyslipidemia and congestive heart failure. Her creatinine clearance is estimated at 18 mL/minute. She has been seen by a gastroenterologist for abdominal pain. He instructed Mirna to take a Fleet’s phosphate enema to clear out her gut prior to a colonoscopy. Choose the correct statements: (Select ALL that apply.)

A. She cannot safely use this laxative due to her poor renal function.
B. She cannot safely use this laxative due to her poor cardiac function.
C. She cannot safely use this laxative due to her anemia.
D. She cannot safely use this laxative because of her age.
E. She can safely use this laxative.

Answer 4

A, B. This laxative is unsafe to use in heart failure, renal disease, hypocalcemia or hyperphosphatemia. It can be fatal if used in patients who cannot tolerate the phosphate load.

Question 5

A patient with constipation presents with a new prescription for Amitiza 24 mcg BID #60. Which of the following is an appropriate generic substitution for Amitiza?

A. Calcium polycarbophil
B. Lubiprostone
C. Docusate
D. Methylnaltrexone
E. Polyethylene glycol

Answer 5

B. Lubiprostone is the generic name of Amitiza.

Question 6

Marla has a pretty good diet, but she is a vegetarian and suffers from iron-deficiency anemia. The physician recommended that Marla use OTC iron twice daily long-term to help correct the problem and prevent anemia in the future. Marla eats primarily whole grains and lots of fruits and vegetables. She is using the iron but finds it has caused constipation with hard, compact stools. She is asking the pharmacist for a laxative recommendation. She is not pregnant and is finished having children. Choose the best recommendation:

A. The preferred laxative is a bulk-forming agent such as psyllium.
B. Counsel her to begin docusate 100 mg twice daily.
C. Due to the compact stool problem, she can use a glycerin suppository.
D. She should begin therapy with MiraLax.
E. Any of the above recommendations would provide benefit.

Answer 6

B. For a patient with adequate fiber intake from her diet who is complaining of hard, compact stools due to iron supplementation, a reasonable recommendation would be to start docusate sodium 100 mg once daily as a first option.

Question 7

Which of the following agents could contribute to constipation? (Select ALL that apply.)

A. Verapamil
B. Sucralfate
C. Magnesium supplements
D. Opioids
E. Misoprostol

Answer 7

A, B, D. Opioids, anticholinergics used for urinary incontinence, antihistamines (including diphenhydramine), and aluminum antacids/complexes, among other agents, cause or worsen constipation.

Question 8

Which of the following are true regarding alvimopan? (Select ALL that apply.)

A. The brand name is Entereg
B. It is safe to use in patients who were on chronic opioid therapy up through admission
C. It is a REMS drug
D. It is given as a SC injection
E. It should be limited to a maximum of 15 doses

Answer 8

A, C, E. Alvimopan (Entereg) is an opioid receptor antagonist used for the prevention of post-operative ileus in patients undergoing various types of surgery. It is a REMS drug and should be limited to 15 doses.

Question 9

Golytely, NuLytely, Trilyte, HalfLytely and MoviPrep can be used prior to colonoscopy or endoscopy procedures to clean out the gut. These laxatives have the following mechanism of action:

A. Stimulants
B. Hyperosmotics
C. Opioid receptor blockers
D. Stool softeners
E. Activates chloride channels in the gut

Answer 9

B. By increasing the osmolarity of the gut, osmotic laxatives cause fluid to move into the gut. NuLytely and Trilyte are sulfate free. HalfLytely and MoviPrep are less volume (2L) than the older Golytely formulation.

Question 10

A mother is asking for help with her seven-month old child. He has diarrhea that started in the morning. Which are correct counseling statements that the pharmacist could provide? (Select ALL that apply.)

A. Do not self-treat diarrhea if there is high fever or blood in the stool; if present, the child must be seen by a doctor. Give fluids, but get to a doctor.
B. Bring the child to the doctor if there is no improvement in two days, or if the situation worsens.
C. Fluid replacement is best provided by products such as Pedialyte or Infalyte.
D. Start loperamide 2 mg with each loose stool.
E. Start bisacodyl 5 mg daily.

Answer 10

A, B, C. Do not self-treat diarrhea if high fever or blood in stool; see physician if no improvement in 2 days (sooner for young children/infants). For moderate-severe fluid loss, replacement is best accomplished with oral rehydration solutions (ORS), which are available in pharmacies and supermarkets.

Question 11

A mother asks the pharmacist what to use to help her two year-old daughter have a bowel movement. The mother states the child “forgets to go” when she is playing, and now it seems too late. The child is squirming and crying. The mother is anxious to help relieve the problem urgently. Choose the best recommendation:

A. Docusate syrup
B. Glycerin suppository
C. Psyllium, in the form of carboxymethylcellulose
D. Bisacodyl
E. Loperamide

Answer 11

B. For a child with constipation, a glycerin suppository (pediatric size or liquid BabyLax) will work right away. If not, a second dose should be sufficient.

Question 12

Charles has little fiber in his diet and states he drinks 4-5 cups of coffee daily. He rarely consumes other liquids. He has no regular physical activity. Which of the following lifestyle measures could help reduce his problem with chronic constipation? (Select ALL that apply.)

A. Increase his physical activity.
B. Consume more fiber, including fruits and vegetables.
C. Limit caffeine and consume more water.
D. Eat larger meals.
E. Substitute alcohol for caffeine.

Answer 12

A, B, C. Inadequate fluid intake, physical activity, and fiber intake are contributory towards worsening constipation.

Question 13

A mother presents to the pharmacy asking for a recommendation for her three year-old child who has a fever and diarrhea. She is concerned that the child has a fever and is uncomfortable. The child did not sleep well last night. Consequently, neither did the mother. The diarrhea appears to be resolving and the mother has taken care not to let the child become dehydrated. Choose the correct recommendation(s) for the fever: (Select ALL that apply.)

A. Baby aspirin
B. Acetaminophen oral suspension
C. Ibuprofen oral suspension
D. Loperamide
E. Bismuth subsalicylate

Answer 13

B, C. If fever/cold symptoms are present, aspirin can rarely cause Reye’s Syndrome in children and is avoided except under a doctor’s care (it may rarely be used in a child with a heart condition, where benefit may outweigh risk).

Question 14

What is the usual method of preventing most cases of opioid-induced constipation?

A. Stimulant laxatives
B. Psyllium
C. Magnesium citrate
D. Bismuth subsalicylate
E. Methylnaltrexone

Answer 14

A. Stimulant laxatives (along with docusate) are the treatment of choice for opioid-induced constipation. Methylnaltrexone is used for patients who have failed both a stimulant and stool softener; it is not the “usual” medication, rather it is the last resort, due to cost and route (SC injection).

Question 15

Carmen is using MS Contin 60 mg BID. She is badly constipated. She is using senna 2 tablets QHS, which is helpful, but complains that the stool is hard to push out. Choose a reasonable recommendation, to be taken daily, to help with the constipation:

A. Add psyllium
B. Add Fleets Phospho-Soda
C. Add docusate
D. Add bisacodyl
E. Add alvimopan

Answer 15

C. Hard stool can be alleviated with a stool softener. Docusate is the most commonly used stool softener.

Question 16

A patient has been using Pepto-Bismol several times daily. His other medications include aspirin, lisinopril, metformin and glipizide. The patient complains of a ringing, “hollow” sound in his ears that is quite bothersome. What is the likely cause of the patient’s complaint?

A. Hypoglycemia
B. Hyperkalemia
C. Salicylate toxicity
D. Hypokalemia
E. Hypermagnesemia

Answer 16

C. Salicylates such as aspirin and bismuth subsalicylate can cause ringing in the ears - this may be a sign of toxicity.

Question 17

Choose the correct statement concerning docusate:

A. It can be used with mineral oil (liquid, oral) if docusate alone is insufficient to soften the stool.
B. A typical dose is 25 mg once daily.
C. Docusate is prescription only.
D. The liquid form, that is sometimes used for children, has a poor taste.
E. Docusate works as an osmotic agent.

Answer 17

D. Docusate comes as an OTC agent. The usual capsule strength is 50 mg and 100 mg. A common dosing schedule is 100 mg BID. Docusate cannot be used with mineral oil. The syrup formulation has a poor taste.

Question 18

Cheryl is pregnant with her first child. She eats a primarily refined diet, but did not suffer from constipation until the second trimester of her pregnancy. Choose the preferred agent:

A. The safest agent is lactulose or polythylene glycol 3350.
B. Counsel her to begin docusate 100 mg twice daily.
C. A preferred laxative is the bulk-forming laxative psyllium.
D. She should begin therapy with MiraLax.
E. She should begin therapy with Milk of Magnesia.

Answer 18

C. Fiber is recommended by pharmacists in pregnancy. It is the first line recommendation according to the American College of Obstetrics and Gynecologists (ACOG).

Question 19

A patient needs to choose a stimulant laxative. Which of the following are considered stimulants? (Select ALL that apply.)

A. Sennosides
B. Bisacodyl
C. Miralax
D. Cascara
E. Docusate sodium

Answer 19

A, B, D. Sennosides, bisacodyl, and cascara all are stimulant laxatives.

Question 20

Which of the following statements concerning MiraLax are correct? (Select ALL that apply.)

A. MiraLax is an OTC formulation of polyethylene glycol.
B. MiraLax works by drawing fluid into the gut.
C. MiraLax causes abdominal cramping and should not be recommended OTC unless a patient has failed stimulant laxatives.
D. It is best to recommend a similar product called GoLytely if an OTC agent is required.
E. MiraLax activates sodium chloride channels in the gut; the primary side effect is nausea.

Answer 20

A, B. Miralax is an OTC formulation of PEG that works as an osmotic agent; it draws fluid into the gut.

Question 21

Choose the correct statement concerning loperamide therapy:

A. This is safe for pharmacists to recommend to infants less than two years old.
B. It is safe to self-treat with loperamide indefinitely if you do not exceed recommended (daily) doses.
C. The correct dose is 4 mg PO after first loose stool initially; then 2 mg after each subsequent stool; not to exceed 16 mg/day.
D. The correct dose is 4 mg PO daily.
E. Loperamide comes in a tablet, suspension, and suppository.

Answer 21

C. Loperamide should not be used when inhibition of peristalsis is to be avoided due to the possible risk of toxic megacolon. Pharmacists should not recommend loperamide in children less than two years old; the use may not be safe. The correct dose of loperamide is 4 mg PO after first loose stool, then 2 mg PO after each subsequent stool not to exceed 16 mg/day.

Question 22

A pharmacist will counsel a patient on the possible side effects of bismuth subsalicylate. The most likely side effects from the use of this antidiarrheal agent are:

A. Blackened tongue and stool
B. Insomnia
C. Loss of appetite
D. Erectile dysfunction
E. Alopecia

Answer 22

A. Patients taking bismuth subsalicylate should be counseled about the most common side effects: blackened tongue and stool.

Question 23

Elaine is a 67 year-old female who is asking for a recommendation for a laxative. Recently, she had a painful wrist sprain and was given hydrocodone-acetaminophen 5/325 mg 1-2 tablets as-needed. The other medications she uses include OTC iron, darifenacin for urinary incontinence and propranolol. Which of Elaine’s medications are most likely contributing to the constipation? (Select ALL that apply.)

A. Hydrocodone
B. Iron
C. Darifenacin
D. Propranolol
E. Acetaminophen

Answer 23

A, B, C. Opioids, iron, and darifenacin are all medications that frequently cause constipation.

Question 24

What is the primary side effect of lubiprostone?

A. Neuropathy (tingling, pain)
B. Pruritus
C. Nausea
D. Confusion
E. Somnolence

Answer 24

C. Lubiprostone is taken with food to help with the nausea. It is dosed twice daily, but some patients need to use just once daily due to nausea. It can also cause abdominal pain and distension.

Question 25

Charles is a 54 year-old male with pre-diabetes, high cholesterol, hypertension and chronic constipation. His diet is largely refined foods, with little fruit or vegetable intake. His allergies are listed as Bactrim, erythromycin, ciprofloxacin and gentamicin eye drops. Charles has been using over-the-counter psyllium to help with constipation. Choose the correct statement/s concerning psyllium: (Select ALL that apply.)

A. Based on his allergies, this is not a safe option.
B. This type of laxative is generally considered first-line treatment for constipation.
C. This is a stool softener, emollient laxative.
D. This is a stimulant laxative.
E. The onset of action is generally about 12-24 hours.

Answer 25

B, E. Bulk-forming laxatives such as psyllium are considered first-line for most patients. They are a reasonable option for patients who have a low-fiber diet. Onset of action is generally 12-24 hours.

Question 26

A female patient is using digoxin for heart failure. She takes the digoxin in the morning. The patient presents to the pharmacy counter with a large container of Metamucil. Choose the correct counseling statement(s): (Select ALL that apply.)

A. Separate the digoxin (about 2 hours before, 2 hours after) from the constipation medicine; otherwise, you may not get enough of the digoxin dose.
B. This agent is a stimulant laxative.
C. Stop taking the digoxin while treating with this agent.
D. Drink adequate fluids.
E. Fiber must be added to the diet slowly or you may get gas and stomach bloating.

Answer 26

A, D, E. Psyllium should be added to the diet slowly to prevent bloating. Digoxin needs to be separated from psyllium by at least 2 hours. Patients should be instructed to drink adequate fluids while taking psyllium.