US Pharm
. 2013;38(12):8-11.


Patients often consult pharmacists for assistance with gastric and digestive complaints, such as diarrhea, gastroesophageal reflux, and bloating. One of the most common complaints is constipation. It is critical for the pharmacist to be fully aware of different options for preventing and treating constipation.

Prevalence and Epidemiology of Constipation

Experts estimate that 15% of the population is affected with constipation, which is approximately 42 million people.1 Within this group, 4 million people suffer from frequent constipation, and 12% to 19% are chronically constipated.2,3 The laxative market in the United States alone is approximately $725 million yearly.2

Constipation affects people of all races and ages, and both sexes.1 However, it is more common in women, in those over the age of 65 years, in non-Causcasians, and in lower socioeconomic classes.1,2 As many as 17% to 45% of women experience constipation during pregnancy.4

Evaluating the Patient’s Medical Record

When a patient complains of constipation, the pharmacist must be alert to the possibility that medications may be the cause.5,6 A host of drugs can be responsible, including narcotic analgesics (e.g., opiate derivatives), antacids with aluminum hydroxide or calcium carbonate, calcium channel blockers, diuretics, Parkinson’s medications, antispasmodics, antidepressants, iron or calcium supplements, and anticonvulsants.1 If a medication is suspected as the cause, the patient should be urged to discuss the problem with the prescriber so alterations to the regimen might be considered.

When to Refer Patients to a Physician

Patients should be referred to a physician in the following situations (among others): 1) the patient has a serious underlying medical condition (e.g., Parkinson’s disease, diabetes); 2) the patient is a possible laxative abuser/misuser (discussed below); 3) constipation has lasted longer than 7 days; 4) the patient also complains of abdominal pain, nausea, and/or vomiting (possible signs of appendicitis); 5) the patient has rectal bleeding or a sudden change in bowel habits that lasts for 2 weeks or longer; 6) the patient has an ileostomy or colostomy; 7) the patient is pregnant or breastfeeding; 8) constipation alternates with diarrhea; 9) the patient has rectal pain or sharp/severe abdominal pain, especially if the latter is accompanied by bloating; 10) stools are thin or pencil-like; 11) the patient has unexplained weight loss; or 12) the patient has used a laxative and/or instituted lifestyle changes, but remains constipated.7-10

Laxative Abusers/Misusers

Pharmacists must also be alert to potential misuse and abuse of laxatives, as mentioned in the referral list above.7,11 There are several types of abuse. For example, wrestlers may be instructed by their coaches to use laxatives to weigh in at a lower number in hopes that they can win a bout. In other cases, persons with anorexia or bulimia intentionally attempt to lose weight by continued use of laxatives, often those containing harsh stimulants such as bisacodyl or senna. Repeated purchases by thin or drastically underweight women should trigger an alarm. Another group of abusers administer laxatives to family members or children for whom they provide care, enjoying the resulting medical attention given to the victim. A final group is patients who use laxatives over the 7-day limit, becoming laxative-dependent.

If pharmacists suspect any of these issues, a refusal to sell is warranted. This can be accomplished by placing laxatives of abuse behind the counter, with a sign informing patients that they must ask the pharmacist for them. This allows the pharmacist to ask questions prior to sale.

Check the Patient’s Age

Laxatives and fiber products carry age limits below which they are not safe for self-treatment.7 Some of the products that are safe down to the age of 2 years include glycerin suppositories and enemas, polycarbophil, docusate, magnesium hydroxide (e.g., Phillips’ Milk of Magnesia), sodium phosphate enemas, mineral oil enemas, magnesium citrate, castor oil, and senna. Products safe only down to the age of 6 years include methyl-cellulose, psyllium, oral mineral oil, and bisacodyl. Carbon dioxide suppositories should not be used by anyone under the age of 12 years, and polyethylene glycol (PEG) 3350 is not safe for those under 17 years.7

Types of Laxatives

PEG 3350: This type (e.g., MiraLAX) is indicated for relief of occasional constipation and generally produces a bowel movement in 1 to 3 days. The manufacturer explains its action as “gently replenishing the water” in the digestive system.12 Patients should not use PEG 3350 without a physician’s advice if they have kidney disease, nausea, vomiting, abdominal pain, a sudden change in bowel habits that lasts more than 2 weeks, or irritable bowel syndrome. Patients should not use it without speaking to a physician or pharmacist if they are taking any prescription drugs. They should stop use and seek physician advice in the following situations: they have rectal bleeding; their nausea, bloating, cramping, or abdominal pain worsens; they develop diarrhea; or they need to use a laxative for longer than 1 week. Patients are directed to fill the cap to the indicated level, which will deliver 17 g, mix the product with a 4- to 8-oz beverage of any temperature, and drink once daily.12

Fiber Replacement Products: These products replace fiber in the diet, acting as dietary supplements.7 They do not force expulsion of fecal contents as stimulants do, but attract water to promote healthy bowel movements. Patients may not notice a difference until 2 to 3 days have passed. These products may be taken up to 3 times daily for 7 days to treat constipation. However, if used to prevent constipation by bulking up the diet, they may be taken indefinitely, unless the patient has a contraindication to their use. Fiber replacement products are inappropriate in several circumstances, including fluid limitations (e.g., renal disease), large intestinal ulcerations or adhesions, partial bowel obstruction, fecal impaction, dysphagia, and gastrointestinal strictures, or in patients who are bedridden and have colonic distension. They are also inappropriate when a prompt, thorough bowel evacuation is needed, as for an upcoming x-ray or colonoscopy.7

Patients must be advised to dilute powdered bulks as advised, and to take them quickly to prevent overthickening that would hamper ingestion.7 If the patient does not dilute the product as needed, it could conceivably block the throat or esophagus to cause choking. Patients should immediately call 911 if they develop chest pain, vomiting, or difficulty in swallowing or breathing. Patients should not take bulks within 3 hours of any medication with a narrow therapeutic index (NTI), such as digitalis or warfarin. Bulks include psyllium (e.g., Metamucil, Konsyl Powder, Hydrocil), calcium polycarbophil (e.g., FiberCon, Konsyl Fiber Tablets), and methylcellulose (e.g., Citrucel).7

Stool Softeners: Docusate has a surfactant effect that softens stool and promotes a bowel movement in 12 to 72 hours.7 It has few adverse reactions. Patients taking medications with NTIs (e.g., digitalis, warfarin) should not use it, and if it is coadministered with mineral oil, the patient can experience systemic lipid granulomatosis. Products include calcium docusate (e.g., Surfak) and sodium docusate (e.g., Colace, Phillips’ Stool Softener, Dulcolax Stool Softener).7

Saline Laxatives: These laxatives osmotically draw water into the bowel to promote a watery bowel movement within 6 to 8 hours.7 Patients should be advised to ingest adequate water (i.e., 8 oz) with them to prevent dehydration. Oral sodium phosphate/biphosphate was discontinued in 2008 for causing acute kidney injury, leaving magnesium-containing products as the only “salines.” They include magnesium citrate, which is occasionally used as a presurgical bowel preparation agent. Another example is magnesium hydroxide, also known as Milk of Magnesia in suspension form. Magnesium should be avoided in patients with adynamic ileus, severe diarrhea, abdominal trauma, intestinal obstruction, heart block, or renal failure, and in patients who require prolonged catharsis.7

Mineral Oil: Mineral oil produces bowel movements in 6 to 8 hours by virtue of its lubricant effect, but the precautions to its use cause it to be a poor choice.7 They include accidental aspiration causing lipid pneumonia, leakage of oily feces, malabsorption of oil-soluble vitamins (i.e., A, D, E, K), and hemorrhagic disease of the newborn if taken in pregnancy (due to vitamin K deficiency).7

Stimulant Laxatives: As is the case with mineral oil, the potential dangers of stimulant laxatives outweigh their benefit, especially in light of the fact that there are far safer choices.7 Stimulant laxatives cause intestinal straining, emesis, abdominal discomfort, electrolyte abnormalities, dehydration, and watery stools. Several stimulants have been taken off of the market due to carcinogenicity (e.g., danthron, aloe, casanthranol, phenolphthalein), but senna (e.g., ex-lax, Senokot), bisacodyl (e.g., Dulcolax Tablets, Fleet Stimulant Laxative), and castor oil remain.7

The drastic, nonphysiological action of stimulant laxatives leads to habituation.13 They empty the distal bowel, but their sustained action also forces the patient to experience loose, watery bowel movements from stool that has not yet reached the distal bowel. When the patient attempts to have a bowel movement the next day, there are no results because that stool has been prematurely evacuated under the drastic action of the stimulant. However, the patient perceives the unsuccessful bowel movement as another case of constipation and incorrectly takes an additional dose of stimulant. Even though the products are labeled to cease use in 7 days, patients may ignore the warning and take them for months or years. For this reason, pharmacists who suspect habituation should urge patients to discontinue the stimulant and attempt to bulk the stools with a fiber replacement product. Patients who remain constipated upon discontinuation should be advised to visit a physician to investigate whether long-term stimulant use has caused permanent damage to the intestinal tract.

Pharmacists should be aware of pregnant women who wish to purchase castor oil to hasten the birth of an “overdue” baby, based on advice on the Internet or from friends or relatives. This practice has resulted in the death of the mother and child.7 Pharmacists must advise the mother to speak to her physician about her desire to initiate labor before the child is due.


What Is Constipation?

Many people have the idea that a daily bowel movement is necessary to remain healthy. If they fail to attain this goal, they may decide they need to force it with the aid of a stimulant laxative. The reality is far more complicated, as “normal” varies from person to person. It is true that some people normally have a single bowel movement daily. But physicians define the normal range of bowel movements as 3 daily to 3 weekly.

Constipation can then be seen as less than your own normal frequency, especially if there are fewer than 3 bowel movements per week. Further, if the stools are harder, drier, or smaller than usual, they become more difficult to eliminate, which are also signs of constipation. You may have a bloated feeling, or a sensation of discomfort in the abdomen caused by trapped feces and gas.

Preventing Constipation With Fiber

The most common cause of constipation is too little fiber in the diet. Fiber comes from plants and has the ability to help the residues of food remain soft as they pass through the stomach and intestinal tract. Foods high in fiber include whole grains, corn, beans, avocado, apples, and nuts. In addition to ingesting more fiber, you can also drink plenty of fluids to help the fibrous materials pass through the digestive tract smoothly.

Fiber Supplements

If eating foods with fiber is a challenge, consider nonprescription fiber supplements such as psyllium (found in Metamucil, Konsyl powder, and Hydrocil products), methylcellulose (Citrucel products), or calcium polycarbophil (FiberCon caplets, Konsyl tablets). You should read and follow all directions for these products. Speak to your pharmacist for assistance with fiber supplements.

Physical Activity

Being physically active seems to help prevent constipation, although the reason is unclear. It is helpful to engage in a daily bout of gentle activity such as walking. Ensure that your body can tolerate the exercise you choose, and speak with your physician for assistance.

Heed the Urge to Have a Bowel Movement

When the urge to have a bowel movement hits, it is important to respond. This helps ensure that
you will continue to perceive that useful signal. People ignore the urge for several reasons, such as being away from home or not wanting to use an unfamiliar toilet. The problem is that continually ignoring this urge will cause it to disappear.

Treatment of Constipation

Constipation is caused by many problems, including potentially dangerous medical conditions and medications you may be taking. For this reason, you should not self-treat constipation for more than 7 days. There are many other precautions on the labels of laxatives that you should read and understand before use.

It is important to Consult Your Pharmacist for assistance with these products. Your pharmacist is specifically trained in helping you choose the appropriate products for preventing and relieving constipation.

Remember, if you have questions, Consult Your Pharmacist.


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