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Vanderbilt-Ingram Cancer CenterVanderbilt-Ingram Cancer Center



Constipation is a decrease in the frequency of stools. It may also lead to hard stools that are painful to pass.

Causes of Constipation:

Constipation is a common side effect from pain medication. It can also be caused by not drinking enough fluids as well as inactivity, immobility, unavailable or inconveniently located bathrooms, depression and anxiety caused by cancer treatment or cancer pain, and a diet low in fiber.

Why is it important to keep constipation under control?

Constipation can lead to fecal impaction (a collection of dry, hard stool in the colon or rectum). Constipation that lasts for more than a few days may cause abdominal pain, cramping, nausea, vomiting and loss of appetite. It is therefore very important that you work with your doctors to keep your bowels regular.

What to do:

  • First: Develop good habits and routine bowel regimen.
  • It is important to pay attention to your colon’s signals.
  • If you ignore the signal, it becomes weaker and weaker. You can strengthen them over time by paying close attention to the signals.
  • The bowels will move most rapidly following meals.
  • Fat-containing foods such as bacon, butter, cream and oil may be useful. These foods stimulate the mucous membranes of your intestines, which should make your stools less hard.
  • Increase fluid intake by drinking 8-ounce glasses of fluid each day (if not contraindicated by kidney or heart disease)
  • Exercise regularly, including abdominal exercises in bed or moving from the bed to chair if you cannot walk.
  • Increase amount of dietary fiber by eating more fruits, vegetables, and whole grain cereals, breads and bran. You must drink more fluids when increasing dietary fiber or you may become constipated.
  • Drink a warm or hot drink about one half-hour before the usual time for a bowel movement.
  • Take only medications prescribed by the doctor.
  • Do not use suppositories or enemas unless ordered by your healthcare professional.

When to call your healthcare provider:

  • If constipation persists for more than 24 hours
  • Associated with any other concerning symptoms such as severe abdominal pain, weight loss, fevers, or weakness.

Constipation Medication

Common medications used to help with constipation

Laxatives can be categorized into the following groups: bulk forming, emollient, hyperosmolar, saline laxatives, and stimulant laxatives.

The bulk forming laxatives work by increasing the water content and bulk of stool. This tends to decrease the time needed for stools to pass through the colon. These are very common laxitives. They must be used with plenty of liquids. Patients who are dehydrated should avoid them. Bulk forming laxatives include the following: Effer-Syllium, Fiberall, Hydrocil, Konsyl, Konsyl-D, Metamucil, Modane Bulk, Perdiem Plain, Reguloid, Serutan, Syllact, V-Lax, Citrucel, and Equalactin, Fiberall, FiberCon, FiberLax, Mitrolan.

The next class is emollient laxatives mainly including mineral oil. It softens stools by moisturizing them. When used as enemas in patients with impacted stool they are effective. A word of caution: mineral oil should NOT be taken orally, especially in elderly patients and those with a difficulty swallowing because it can enter the lungs and cause pneumonia. It also can cause anal seepage of stool.

The hyperosmolar class includes MiraLax, lactulose – Cephulac, Cholac, Chronulac, Constilac, Constulose, Duphalac, Enulose, Evalose, Heptalac, Lactulose PSE, glycerine and sorbitol. All of these work by reducing the amount of water absorption from the colon. The stools usually become soft but are still formed. Gas and bloating can be produced by Lactulose and sorbitol because they are digested in the colon by bacteria.

The next class – saline laxatives act much in the same way as the class above because they also draw water into the colon. They include Milk of Magnesia and Evac-Q-Mag.

Cascara Sagrada, Black Draught, Senexon, Senna-Gen, Senokot, Bisac-Evac, Bisacodyl Uniserts, Bisco-Lax, Carter’s Little Pills, Clysodrast, Dacodyl, Deficol, Dulcolax, Feen-A-Mint, castor oil and aloe are stimulant laxatives. Stimulant laxatives cause fluid accumulation in the intestines. They tend to be overused and can cause serious side-effects such as severe diarrhea and damage to the nerves of the intestines when used for long periods of time and when used at higher doses than recommended. Aloe containing preparations almost always produce cramps and are not recommended.