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Chronic Constipation

Chronic Constipation: A Pharmacist’s Overview

Effective management of chronic constipation with lifestyle, fiber, and meds.

Introduction

Chronic constipation is a prevalent condition characterized by infrequent bowel movements (fewer than three per week), difficulty passing stools, hard stools, or the need for manual assistance during defecation. Patients may also report a sensation of incomplete evacuation. This condition can be categorized as:

  1. Primary (functional) constipation, which involves a dysfunction of the colon or rectum.
  2. Secondary constipation, which results from underlying medical conditions or medications.

Functional constipation is further classified into

  • Slow transit constipation: Caused by delayed fecal passage through the colon.
  • Rectal outlet dysfunction: Linked to insufficient rectal propulsive forces or increased resistance to stool evacuation.

RxPharm-adv

Evaluation of Chronic Constipation

Conduct a Comprehensive History and Physical Examination

  • Identify secondary causes of constipation, such as mechanical obstruction, medication use (e.g., opioids, calcium channel blockers), systemic illnesses (e.g., hypothyroidism, diabetes), or neurologic disorders (e.g., Parkinson’s disease).
  • Screen for alarm symptoms like weight loss, rectal bleeding, anemia, or age >45 years without prior colorectal cancer screening, and refer for colonoscopy if present.

Perform a Digital Rectal Examination (DRE)

  • Assess patients in the left lateral decubitus or jackknife position to identify structural abnormalities, such as hemorrhoids, masses, anal fissures, or rectocele.
  • Evaluate pelvic floor dysfunction by checking resting sphincter tone, ability to tighten the sphincter, and pelvic floor movement during simulated defecation.

Use Specialized Testing for Pelvic Floor Dysfunction

Order anorectal manometry or balloon expulsion testing when the DRE is nondiagnostic but suspicion for dyssynergic defecation remains.

Evaluate Intestinal Transit Time

Conduct a colon transit study or a “sitz marker study” in patients without evidence of pelvic floor dysfunction who do not respond to initial therapy to confirm slow intestinal transit as the underlying cause.

Refer Patients with Alarm Symptoms

Ensure colonoscopy is performed in patients presenting with weight loss, anemia, rectal bleeding, or concerning symptoms indicative of an underlying neoplastic process.

Management

Encourage Lifestyle Modifications

Increase dietary fiber intake to 20–35 g per day using sources like psyllium or kiwifruit, which has shown comparable efficacy to psyllium with fewer side effects. Promote regular physical activity and adequate hydration to enhance bowel motility.

Initiate Laxative Therapy if Lifestyle Measures Fail

  • Use osmotic laxatives like polyethylene glycol (PEG) or magnesium oxide as first-line options.
  • Consider stimulant laxatives like senna or bisacodyl for short-term or rescue therapy. Limit bisacodyl use to less than four weeks.
  • Avoid docusate for constipation management, as studies demonstrate its ineffectiveness.

Drug Mechanism of Action Dosing Side Effects Comments
Linaclotide Guanylate cyclase-C
agonist		 Initial: 72–145
mcg daily
Maximum: 290
mcg daily		 Diarrhea (though often
improves after 1–2
weeks on therapy)		 Should be taken without food,
at least 30 minutes
before the first meal of the day.
Plecanatide Guanylate cyclase-C
agonist		 3 mg daily Diarrhea Contraindicated in patients under 6
years of age and should be avoided
in those under 18 years of age.
Prucalopride 5-HT4 agonist Initial: 1 mg
daily
Maximum: 2 mg
daily		 Diarrhea, abdominal
pain, headache, nausea		 Suicide attempts reported
in clinical trials but there has been
no causal association between
use of prucalopride and suicide.
Lubiprostone Chloride channel
activator		 24 mcg twice
daily		 Nausea, diarrhea Nausea is dose-dependent and
may be improved by taking with meals.

Explore Advanced Pharmacologic Options

  • Lubiprostone: Activate chloride channels to improve bowel movements, stool consistency, and reduce abdominal bloating and discomfort.
  • Linaclotide and plecanatide: Enhance guanylate cyclase-C activity to increase spontaneous bowel movements, improve stool consistency, and alleviate bloating. Avoid plecanatide in patients under 18 years due to safety concerns.
  • Prucalopride: Use for refractory cases to improve bowel movement frequency. Monitor patients for suicidal ideation or mood changes, as noted in clinical trial warnings.

RxPharm-adv

Take-home points

Chronic constipation is a common condition requiring a multifaceted approach for effective management. Here are key takeaways for pharmacists when evaluating and treating chronic constipation...

  1. Start with lifestyle interventions, such as increasing dietary fiber, physical activity, and hydration.
  2. Fiber supplementation, like psyllium or kiwifruit, can improve symptoms with fewer side effects.
  3. Use osmotic laxatives (e.g., polyethylene glycol) as first-line treatment, with stimulant laxatives for short-term relief.
  4. Avoid docusate, as it has been shown to be ineffective for treating constipation.
  5. Consider advanced treatments like lubiprostone, linaclotide, plecanatide, or prucalopride for patients unresponsive to standard therapies.
  6. Monitor for side effects such as diarrhea, abdominal pain, or nausea with medications.
  7. Avoid plecanatide in children under 6 years and use caution in those under 18.
  8. Refer patients with alarm symptoms, such as weight loss or rectal bleeding, for colonoscopy.

References

  1. Cho YS, Lee YJ, Shin JE, et al. 2022 Seoul Consensus on Clinical Practice Guidelines for Functional Constipation. J Neurogastroenterol Motil. 2023;29(3):271-305.
    2. Show more references

Keywords: Chronic constipation, Lifestyle interventions, Dietary fiber, Physical activity, Hydration, Fiber supplementation, Psyllium, Kiwifruit, Osmotic laxatives, Polyethylene glycol, Stimulant laxatives, Senna, Bisacodyl, Docusate, Ineffective treatment, Lubiprostone, Linaclotide, Plecanatide, Prucalopride, Chloride channel activator, Guanylate cyclase-C agonists, 5-HT4 agonist, Side effects, Diarrhea, Abdominal pain, Nausea, Special populations, Plecanatide contraindication, Colonoscopy, Alarm symptoms, Rectal bleeding, Weight loss, Anemia

Senior clinical pharmacist, "Pharmacy Practice Department, Tanta University Hospital, Egypt". Medical content writer.