Pharmacology

Constipation

Case Study

Patient Profile

Name: Randy

Age: 56 years old

Gender: male

Current Medications

None

History of Present Illness

Randy is a 56-year-old man presenting with complaints of constipation. His normal bowel pattern is having a bowel movement every one to two days. His last bowel movement was four days ago, and it was very difficult to pass. He is occasionally passing gas. He feels mildly bloated. He was recently discharged from the hospital for two-vessel coronary artery bypass graft. He realizes he is not as active as he used to be, but he just does not have as much energy since the hospitalization. He has been attending cardiac rehab per his hospital discharge instructions and has a follow-up appointment with cardiology next week. He has not had any lightheadedness, passing out, chest pain, shortness of breath, abdominal pain, nausea, vomiting, anal pain, diarrhea, or bloody stools.

Relevant Assessment

Abdomen: mildly convex abdomen. Bowel sounds hypoactive in all quadrants. Mild diffuse tenderness. No hepatosplenomegaly, masses, bruits, or thrills.

Kidney’s ureters bladder (KUB) radiograph obtained. Results: moderate stool burden throughout the large intestine. No obstructive patterns. Findings consistent with constipation.

No other expanded review of system (subjective data) or examination (objective data) has an impact on the diagnosis reviewed in this case.

Differentials

Functional constipation, Hirschsprung’s disease, neurological condition (multiple sclerosis, Parkinson Disease, spinal cord injury), metabolic disorder (hypothyroidism, diabetes), structural anal disorders (anal fissures, hemorrhoids) medication adverse effect (opioids, antidepressants), irritable bowel syndrome-constipation predominant, bowel obstruction

Diagnosis

Functional constipation

Diagnostic Testing

KUB done. No further testing at this time.

Referrals

None at this time

Patient/Provider Collaborative Goals

Randy will have sufficient bowel movements by time of planned follow-up.

Therapeutic Interventions

  1. Describe a first-line pharmacologic treatment: Include drug name, dose and formulation, frequency, and length of treatment at this dose.
    Answer:

    Psyllium (Metamucil): 3.4g of powder in 8 oz of liquid one to three times a day by mouth for constipation until successful bowel movement, then daily to maintain bowel movements three times a week thereafter. Hold the medication and contact the office for loose bowel movements or diarrhea.

    • Drug Mechanism of Action:
      Answer:

      Psyllium is a soluble fiber that absorbs water in the intestine and forms a thick substance that stimulates peristalsis and increases the speed of intestinal contents.

    • Contraindications if applicable:
      Answer:

      Hypersensitivity to psyllium or any of the product components. Additionally, fecal impaction and gastrointestinal intestinal obstruction are contraindications. Furthermore, caution should be used in a patient with a history of esophageal strictures, ulcers, stenosis, intestinal adhesions, or dysphagia.

  1. Therapeutic advisement and monitoring: (include any specific instructions that apply, such as when to take the medication, if there are foods to avoid, storage issues, etc; include what laboratory/other (i.e., EKG) test monitoring to expect and how often and monitoring for adverse effects both common and serious)
    Answer:

    Specific Instructions: Instruct the patient that the psyllium powder must be mixed in a full 8 oz glass of water or juice. Advise the patient to drink enough non-alcoholic non-caffeinated beverages per day so that when the patient urinates in the toilet, the water is minimally yellow tinted or clear. Educate the patient that adequate daily fiber intake is 30g/day. Advise the patient to include healthy fiber sources such as fruits, vegetables, whole grains, etc.
    Strongly encourage the patient to make sure they are following their cardiac rehab exercise plan; movement can help get the bowels to start moving like normal again. Being sedentary promotes problems with bowel immobility and can lead to bowel obstruction, which can be fatal.
    Remind the patient that he might not resume his usual daily or every other day bowel movements right away due to his change in diet and activity level. The goal should be three bowel movements per week once the patient begins to have sufficient bowel movements again. Counsel the patient to avoid straining during a bowel movement which can lead to passing out and subsequent injury.
    Instruct the patient to call the office if they experience abdominal cramps, constipation despite proper use of the medication, or intestinal obstruction symptoms, including nausea, vomiting, diarrhea, difficulty swallowing (esophageal obstruction), or rectal bleeding.

    • Therapeutic Monitoring: Monitor for relief from constipation.
    • Serious Adverse Effects:
      • Gastrointestinal: Esophageal or intestinal obstruction
      • Allergic reaction including anaphylaxis
  1. Planned follow-up should consider adverse effect monitoring, dose adjustment considerations, and decisions about continuing versus discontinuing. In this case, planned follow-up would be:
    Answer:

    Follow-up office visit in three days. Advise the patient to call the office sooner if he develops abdominal cramps/pain, continued constipation despite proper use of the medication, or intestinal obstruction symptoms including nausea, vomiting, diarrhea, difficulty swallowing or rectal bleeding.

Review Questions

Click the arrow to expand the section and view the correct answers.

  1. Non-pharmacologic interventions for patients with functional constipation include:
    1. Increasing fatty foods to promote soft stools
    2. Increasing spicy foods to promote bowel movements
    3. Increasing fiber in the patient’s diet and exercise
    4. Moderate use of alcohol to help the patient relax and move their bowels
Answer:

C. Increasing fiber in the patient’s diet and exercise

Feedback: Non-pharmacologic interventions for patients with functional constipation include increasing fiber in the patient’s diet and exercise. Additionally, maintaining good hydration helps avoid constipation.

  1. Senna is considered safe for breastfeeding patients with functional constipation.
    1. True
    2. False
Answer:

A. True

Feedback: Senna is considered safe for breastfeeding patients. Bisacodyl and polyethylene glycol have not been directly studied in breastfeeding patients.

  1. The best management for constipation in a pregnant female is which of the following:
    1. Stimulant laxatives
    2. Surfactant laxatives
    3. Good hydration, increased fiber, and exercise
    4. No laxatives can be used in pregnancy they are contraindicated
Answer:

C. Good hydration, increased fiber, and exercise

Feedback: It is best to avoid laxatives in pregnant patients if possible. Using interventions of increased hydration, increased fiber, and increased exercise (even walking after meals) may be sufficient to address constipation. Stimulation of the gastrointestinal tract may induce labor. However, if more conservative measures are not helpful, non-stimulant laxatives are better choices.

  1. For which patient is magnesium citrate contraindicated?
    1. A patient with recent myocardial infarction
    2. A patient with functional constipation and no underlying medical conditions
    3. A patient with an abdominal hernia near the umbilicus
    4. A patient with reduced estimated glomerular filtration rate (eGFR) of 30 mL/min/1.73 m2
Answer:

D. A patient with reduced estimated glomerular filtration rate (eGFR) of 30 mL/min/1.73 m2

Feedback: Magnesium salts and sodium phosphate should not be utilized in patients with renal impairment. Impaired renal function may lead to toxic levels of magnesium or phosphate. A normal eGFR is greater than 60 mL/min/1.73 m2.

  1. Which of the following laxatives is NOT approved for irritable bowel syndrome with constipation (IBS-C)?
    1. Polyethylene glycol 3350
    2. Docusate sodium
    3. Senna
    4. Lubiprostone
Answer:

B. Docusate sodium

Feedback: Polyethylene glycol 3350, Senna, Lubiprostone, and psyllium are among the options approved by the Food and Drug Administration to treat IBS-C.

  1. A parent brings their kindergartener in for an office visit with concern that the patient is not having daily bowel movement. The parent reports concern that since starting kindergarten a couple of weeks ago they are fearful the child is constipated. The bowel movement observed a couple of days ago was soft, and smooth with no cracks on the surface. It was his typical light brown color and they did not see any blood. Prior to starting kindergarten a couple of weeks ago, there was never a concern for constipation. The patient is asymptomatic, active, and has a full range of affect. Expanded review of system (subjective data) and examination (objective data) are all normal today. What is your response to the concern about the child being constipated?
    1. Your child is constipated; let’s start the child on docusate sodium and senna daily until the child is moving their bowels daily
    2. Your child is constipated; I will send you to the emergency department for a bowel cleanse to make sure there is no obstruction
    3. Your child is not constipated, but let’s start the child on methylcellulose to prevent constipation from developing
    4. Your child does not meet the criteria for constipation as the stool was soft when they had a bowel movement a couple of days ago.
Answer:

D. Your child does not meet the criteria for constipation as the stool was soft when they had a bowel movement a couple of days ago.

Feedback: To make the diagnosis of constipation Rome IV criteria require symptoms be present for a month or more and at least two of the following: two or less bowel movements per week, painful or hard bowel movements, large bowel movement that may clog the toilet, and incontinence of stool at least once a week in a toilet trained child. This patient in this question would be helped with information about good hydration, plenty of physical activity, and inclusion of foods high in fiber.

  1. You are seeing a patient who has been diagnosed with cancer that is not curable. Part of the patient’s treatment plan is opioid analgesics. The patient is complaining today of constipation with infrequent and hard to pass stools. The patient has recently been trying to increase fluid intake, increase fiber, and has used docusate sodium, senna, and even tried magnesium citrate. The patient does not have much energy to increase physical activity but has attempted to walk a little more often. The patient wants to know if there is anything you can suggest for treating constipation. You consider which of the following due to the patient’s use of opioid analgesics:
    1. Methynaltrexone
    2. Bisacodyl
    3. Psyllium
    4. Castor oil
Answer:

A. Methynaltrexone (Relistor)

Feedback: Methynaltrexone (Relistor) is specifically used to treat opioid-induced constipation. It acts by µ receptors in the intestines.

  1. You have a patient meeting the criteria for constipation. The patient is asking how long it will take to have a bowel movement after taking the bisacodyl suppository you recommend. Your best answer is:
    1. 6-12 hours
    2. 5-20 minutes
    3. 15-60 minutes
    4. A day or so
Answer:

C. 15-60 minutes

Feedback: The onset of action for a bisacodyl suppository is 15-60 minutes. A bowel movement typically occurs within an hour after use of a bisacodyl suppository. Inform the patient to stay in proximity to the bathroom.

References

Condina Leik, M. T. (2025). Common disorders in geriatrics. In FNP Certification Intensive Review (pp. 493–512). Springer Publishing.

Rosenthal, L. D., & Burchum, J. R. (2026). Laxatives. In Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (3rd ed., pp. 594–600). Elsevier.

Rosenthal, L. D., & Burchum, J. R. (2026). Opioid analgesics, opioid antagonists, and nonopioid centrally active analgesics. In Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (3rd ed., pp. 181–191). Elsevier.

Up To Date. (2025). Psyllium: Drug information. Up To Date®. Retrieved June 11, 2025 from https://www.uptodate.com/contents/psyllium-drug-information

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Be Prepared for Your Nurse Practitioner Clinical Readiness Exam Copyright © 2026 by Elizabeth Heavey, Renee Biedlingmaier, Colleen Burgoyne and Carnel C. Jackson is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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