Constipation

Overview

The primary objective of managing constipation is to support patients in having regular and adequate bowel movements, based on the individual’s preference and functional status. Constipation is described as difficult, hard, or incomplete emptying of the bowels, and/or less frequent bowel movements than usual and is subjective in nature. It is common in patients with chronic disease and is often multifactorial.

If patients are on regularly scheduled opioids, consider ordering a regular bowel routine to prevent or manage constipation. With severe constipation, additional signs and symptoms can include nausea/vomiting, abdominal cramping, distension, or overflow diarrhea.

When assessing constipation, rule out a bowel obstruction
- Signs and symptoms of a bowel obstruction may include nausea/vomiting, high pitched/absent bowel sounds, distended abdomen, and abdominal cramping/pain
- If a bowel obstruction is suspected, consider obtaining an abdominal flat plate x-ray to assess the severity of constipation and rule out a bowel obstruction. This can also help to determine whether a bowel clean out is needed prior to starting new bowel regimen
Non-pharmacological and pharmacological interventions are often required together
Be aware that constipation may trigger hepatic encephalopathy in patients with cirrhosis

Step 1 Consider the Underlying Causes of Constipation

Rule out a bowel obstruction:

Signs and symptoms of a bowel obstruction (e.g. nausea/vomiting, high pitched/absent bowel sounds, distended abdomen, abdominal cramping/pain)
Consider obtaining an abdominal flat plate x-ray to assess the severity of constipation and rule out a bowel obstruction. This can also help to determine whether a bowel cleanout is needed prior to starting new bowel regimen

Decreased mobility
Advanced age
Mood Disorders (e.g. depression, anxiety, stress)
Low fiber intake
Low fluid intake
Adverse effects of medications (such as opioids, oral iron supplements, antacids, calcium supplements)
Metabolic disturbances (e.g.hyperglycemia, hyper/hypocalcemia, hypothyroidism, diabetes)
Bowel conditions (e.g. irritable bowel syndrome)
Neurological conditions (e.g. parkinson’s, multiple sclerosis, spinal cord injury)
Mechanical obstruction of the bowel or rectum
Structural abnormality (e.g. fecal impaction, obstruction, lesions/adhesions)
Miscellaneous (e.g. ascites, colorectal malignancy)

Step 2 Non-pharmacological Management of Constipation

General Principles

Non-pharmacological measures should be considered in all patients where the symptom impacts quality of life or ability to function
Regularly monitor bowel pattern and patient satisfaction to adjust to desired effect
Provide patients with the One:carepath Patient Handout Constipation
In the context of advanced, progressive diseases with established constipation, the following are not recommended:
- increasing oral fluids
- encouraging exercise
- use of stool softeners
Avoid high fibre in patients with reduced oral intake, frailty, reduced mobility, and severe advanced illness

Encourage the Following behaviour

Increase dietary fiber intake, if appropriate (e.g. flax seeds, psyllium, unprocessed bran, whole grains, fruits, vegetables); avoid in patients with reduced oral intake, frailty, reduced mobility and severe advanced illness
- Some higher fiber foods such as bran, beans, lentils, nuts and seeds are also high in phosphorus and potassium (e.g. prunes, prune juice) and may need to be limited in patients with advanced chronic kidney disease (advanced CKD)
- Consider a referral to a Registered Dietitian for nutritional counseling
Hydration management
- Increasing hydration (2.0 L/day for women and 3.0 L for men); avoid in the context of advanced, progressive diseases complicated by volume overload (e.g. advanced CKD, cirrhosis, heart failure) or severe hyponatremia
- Avoid vasodilators such as coffee, alcohol, spices, and hot water
Encourage regular bowel routine
- Regular toileting upon waking up and post meals
- Avoid ignoring the urge to have a bowel movement
- Avoid straining
- Toilet in sitting position with a use of a raised toilet seat, foot stool or bedside commode
Encourage physical exercise, where appropriate
Manual Disimpaction: only if needed and if pharmacological therapy has failed
- In cases of severe constipation, if there is stool impaction (solid immobile stool in the rectosigmoid), carry out manual fragmentation (if needed), followed by a soap suds enema. Once the stool impaction is cleared, consider a Polyethylene Glycol 3350 (PEG) bowel cleanout
- The technique is contraindicated in patients with bowel obstruction

Step 3 Pharmacological Management of Constipation

General Principles

The goal of therapy is to balance symptom control with careful protection of physical function and cognition
Oral measures are preferred and reduce the need for rectal interventions
If standard laxatives are ineffective, see AHS Constipation Primary Care Pathway or talk to GI specialist regarding possible newer therapies (e.g. Secretagogues such as Linaclotide or Prokinetics such as Prucalopride). These are more costly and may not be covered by existing drug plans
In difficult to treat cases, an abdominal flat plate x-ray should be carried out in order to identify fecal loading, stool distribution and determine if a full bowel cleanout is needed before starting or changing to a new bowel regimen, or consult palliative care

Special Considerations for Opioid Induced Constipation (OIC)

When opioids are started, prophylactic laxatives are usually required, and should be continued for the duration of opioid use
Sennosides may be the most useful single laxative when an opioid is prescribed. Also, a combination of a stimulant (e.g. sennosides), plus an osmotic laxative to moisturize and to soften stool (e.g. lactulose or polyethylene glycol (PEG)) may be required
As the dose of opioids increases, the dose of laxatives often needs to increase, with dosing twice daily (breakfast/bedtime) or even three times daily, up to the maximum recommended or tolerable
When OIC suspected, and response to other standard measures is inadequate, opioid antagonists (e.g. methylnaltrexone, naloxegol) may be suitable with specialist advice. Use only after failure of standard laxative therapy, to augment, not replace laxatives

First Line Therapy (Bulk Forming Laxatives)

Psyllium Husk First-line Agent

2.5 to 30 g per day in divided doses

Recommended to take with adequate fluids (at least 8 ounces to prevent choking)

First Line Therapy (Osmotic Laxatives)

Polyethylene Glycol (PEG 3350) First-line Agent

17 grams per oral daily
Maximum dose: Titrate to effect or max 68 g/day in divided doses

It is important to discontinue all other maintenance laxatives prior to initiation of osmotic laxative therapy; if response is not optimal after 3 days, other laxative therapy may be reinitiated
Onset of action: within 24 hours
Excess use can potentially result in volume and electrolyte loss. If this is a risk, use not recommended for longer than 1-2 weeks
Can be used as 1st line treatment for liver cirrhosis if no hepatic encephalopathy

Lactulose First-line Agent

15-30 mL oral once to three times per day
Maximum dose: titrate to effect – max 60ml per day
For patients with hepatic encephalopathy, titrate to 2-3 soft bowel movements per day

Onset of action: up to 24 to 48 hours

First Line Therapy (Stimulant Laxatives)

Sennosides First-line Agent

8.6 mg-17.2 mg (1-2 tablets) orally; nighttime
Maximum daily dose: 68.8 mg orally, e.g. 4 tablets twice per day

Onset of action: 6-24 hours
Use for short-term treatment and not as maintenance therapy unless at end of life
Patients may experience painful cramps; osmotic laxatives are often preferred

Second Line Therapy (Suppositories)

Glycerin or Bisacodyl Suppository Second-line Agent

One adult suppository (10 mg) once daily or as needed

Onset of action: 15-30 minutes

Second Line Therapy (Stimulants)

Bisacodyl Second-line Agent

Oral: 5-15 mg per oral daily
Rectal: 10 mg daily

Onset of action: 6-12 hours (oral), 25 min-1 hour (rectal)
Not recommended for more than 1 week

Third Line Therapy (Alternative Treatments)

Sodium-phosphate Enema (Fleet Enema) Third-line Agent

4.5 oz enema as single dose

Associated with decline in eGFR in elderly

Magnesium citrate or hydroxide or sulfate (Epsom Salt) Third-line Agent

Citrate: Magnesium citrate 15g/300ml dose 75-150 ml per day, drink 250ml water after
Sulfate: 1 tsp in 4 oz warm water daily
Magnesium hydroxide: 400mg/5ml dose 30-60 ml per day

Sodium-phosphate Enema (Fleet Enema)

Contraindicated in patients with severe kidney disease and heart failure

Contraindicated in patients with appendicitis and obstructive bowel disease

Fourth Line Therapy (Special Considerations) - Specialist referral recommended

Secretagogues (Linaclotide) Fourth-line Agent

Consider GI specialty or palliative care consultation if these medications are required. These are more costly and may not be covered by existing drug plans. Visit the AHS Constipation Primary Care Pathway

Prokinetics (Prucalopride) Fourth-line Agent

Peripherally acting μ-opioid receptor antagonists (PAMORAS) Fourth-line Agent

This class of medications are effective against Opioid Induced Constipation (OIC) and has limited ability to cross blood brain barrier (e.g. alvimopan, naloxegol, methylnatrexone, axelopran). Adverse side effects include diarrhea, abdominal pain, nausea and vomiting
Consider GI specialty or palliative care consultation if these medications are required. These are more costly and may not be covered by existing drug plans. Visit the AHS Constipation Primary Care Pathway