Constipation Medication

What is Constipation?

Constipation is a common condition characterized by trouble passing stool.  The stool tends to be hard and pellet-like.  Patients often attempt to pass stool by bearing down forcefully (straining) – this may eventually lead to the development of hemorrhoids and diverticulosis.  Both of these latter conditions lead to rectal bleeding.  The condition is typically related to inadequate physical activity, fluid intake and dietary fiber consumption.  Other causes are related to medication use (e.g., opiate analgesics), another underlying condition (e.g., hypothyroidism, colon cancer), or impaired intestinal motility.

Constipation is a frequent problem in the elderly population.  Severe cases of constipation and fecal impaction can lead to confusion and delirium in patients with advanced age.

What Causes Constipation?

Constipation is typically caused by the following factors:

  • Inadequate physical activity – exercise promotes the movement of feces down the colon
  • Inadequate fluid intake – most people require 1.5-2 L fluids daily and this requirement increases with exercise and illness (e.g., infection)
  • Low dietary fiber consumption – the average person typically requires about 30g of fiber in their diet daily
  • Use of opiate analgesics for pain
  • Other medication conditions
    • Hypothyroidism
    • Hyperparathyroidism,
    • Hypercalcemia
    • Colon cancer (mostly in people age >50)
  • Impaired intestinal motility – due to diabetes mellitus, advanced age

These features either lead to slow transit of stool through the colon or mechanical obstruction of stool through the gastrointestinal tract.  Colon cancer is an important consideration in patients with a prior history of colon cancer, first degree relatives with colon cancer, history of ulcerative colitis, or age >50.  Colon cancer may cause unintentional weight loss, blood in the stool, changes in stool caliber (e.g., pencil thin stool), and trouble passing stool.

How Common is Constipation?

Constipation is exceedingly common in the United States and responsible for frequent primary care visits.  This is particularly true in the elderly population.  The condition may require referral to a gastroenterology specialist if first-line and conservative measures were unsuccessful or the patient needs a colonoscopy.

The prevalence of constipation in North America is approximately 12%-19%.  Constipation in the United States and the United Kingdom appears to be more common in women, non-Caucasians, and people age >60.  The prevalence of chronic constipation increases with age, especially in individuals age ≥ 65.  In this age group, about 26% of men and 34% of women have problems with constipation.

Signs and Symptoms

Symptoms of constipation often include:

  • Straining on defecation
  • Difficulty passing stool
  • Hard pellet-like stool

Severe constipation can result from a condition called fecal impaction – this means that the stool literally impacts or blocks the rectal passage, not allowing any stool to pass.  This is particularly common in the elderly and may lead to confusion or delirium.

Constipation also frequently results in the development of hemorrhoids and diverticulosis.  Hemorrhoids are characterized by dilated veins in the rectum – these veins often bleed during bowel movements.  Patients may complain of rectal itching or pain.  Hemorrhoids will occasionally thrombose (form a blood clot), which can be very painful and require outpatient surgery.

Diverticulosis is characterized by outpouchings in the colon – this usually affects the sigmoid colon, which is terminal part of the large intestine.  The outpouching in diverticulosis may bleed, resulting in significant rectal bleeding in some cases requiring hospitalization.  Diverticula can also become infected and inflamed, resulting in a condition termed diverticulitis.  This requires treatment with antibiotics.  Some patients have recurrent diverticular bleeds or diverticulitis need surgery to remove the portion of the bowel that is affected.

How is Constipation diagnosed?

The diagnosis of chronic constipation is suggested based on symptoms and physical examination.  Your doctor may order laboratory and imaging studies to rule out underlying medical conditions that may be contributing to your symptoms.

Commonly ordered blood tests include a CMP (comprehensive metabolic panel), calcium level, thyroid function (TSH, free T4), CBC (complete blood cell count).  They will also usually screen for diabetes.  X-rays or CT scan can sometimes demonstrate constipation, but these are generally not required unless constipation is very severe or an underlying cancer is suspected.

Patients may require a colonoscopy performed by a gastroenterology specialist.

Constipation Medication and Treatment

Constipation is initially treated with dietary and lifestyle changes.  Patients are encouraged to increase their amount of dietary fiber – this can usually be achieved by increasing consumption of fruits, vegetables, beans, nuts, and whole grain foods. Most individuals should also be drinking about 1.5-2L clear fluids on average daily.  Physical activity is also encouraged in patients with constipation who can tolerate exercise.  Most people are recommended to exercise for 30 minutes, 3 times a week.

If there is a known underlying cause of constipation – hypothyroidism, opiate use, colon cancer – these conditions should be reversed or treated.

Constipation may require treatment with laxatives, which typically include

  • Bulk-forming agents – Metamucil (psyllium), Citrucel (methylcellulose)
  • Stool softeners – Colace (docusate)
  • Stimulant laxatives – Senokot (senna), Dulcolax (bisacodyl)
  • Osmotic laxatives – Constulose (lactulose), MiraLax (polyethylene glycol 3350)

Most of these agents are taken orally – occasionally you may require a rectal suppository (Dulcolax) or fleet enema.  Fecal impaction often requires manual disimpaction.  In severe cases, it may require surgery.


  1. Bharucha AE, Pemberton JH, Locke GR 3rd. American Gastroenterological Association technical review on constipation. Gastroenterology 2013; 144:218. -
  2. Lee-Robichaud H, Thomas K, Morgan J, Nelson RL. Lactulose versus Polyethylene Glycol for Chronic Constipation. Cochrane Database Syst Rev 2010; :CD007570. -

Constipation Medicine

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.