Constipation: Uncomfortably Common

Constipation is defined as a condition in which an individual has fewer than 3 bowel movements each week or has bowel movements that are hard and difficult to pass.

It is considered to be a common gastrointestinal complaint affecting an estimated 42 million individuals in the United States.1 Causes include certain medical conditions and pharmacologic agents, physiologic and psychological issues, and lifestyle or dietary habits (Table 1^1,2). Pharmacists are in a pivotal position to aid patients in the selection of the best products to treat constipation, as well as to identify patients with a higher risk of developing constipation due to the use of certain pharmacologic agents (Online Table 2^1,3).

Constipation can affect anyone at any age, but it does occur more frequently during pregnancy, after childbirth, after surgery, and from taking certain medications.² Although most cases are easily managed with proper treatment, some individuals suffer from chronic constipation that can lead to other complications, such as hemorrhoids, anal fissures, and fecal impaction.^2-4 Patients with chronic or repeated episodes of constipation should be advised to seek further medical care from their primary health care provider when warranted.

Signs and Symptoms

Whereas the incidence and severity of constipation vary from patient to patient, the most common signs and symptoms include the following^1,2:

• Stomach discomfort or cramping that is resolved by a bowel movement

• Straining during bowel movements

• Fewer bowel movements than usual

• Bloating or abdominal discomfort

• Hard, compacted stools that are difficult to pass

Prevention and Treatment

A host of nonprescription products are on the market for preventing and treating constipation (Online Table 3^2,4). The selected treatment depends on the cause, severity, and duration of the constipation. Treatments may include one or more of the following: increasing dietary fiber; using fiber supplements, stimulant laxatives, saline laxatives, osmotic laxatives, and/or stool softeners; and making exercise and lifestyle modifications. Prior to recommending any product, pharmacists should ascertain if self-treatment is appropriate and refer patients to their primary health care provider for further evaluation and treatment, when warranted.

Table 2: Examples of Drugs that May Induce Constipation^1,3

• Analgesics
• Antacids
• Anticholinergics
• Anticonvulsants
• Antimuscarinics
• Benzodiazepines
• Calcium channel blockers
• Calcium supplements
• Diuretics (eg,hydrochlorothiazide, furosemide)
• Antispasmodics
• Iron supplements
• Hyperlipidemic agents
• Hypotensives (eg, angiotensin-converting-enzyme inhibitors, beta blockers)
• Muscle relaxants
• Opioids
• Parkinsonian agents
• Sedative hypnotics
• Sucralfate
• Tricyclic antidepressants
• Vinca alkaloids

Bulk-Forming Agents

As a group, bulk-forming agents—such as methylcellulose, polycarbophil, and psyllium—are the treatment of choice in the majority of constipation cases since their mechanism of action closely resembles the physiologic mechanism that promotes defecation.² They are indicated as short-term therapy and prophylactically in patients who should refrain from straining during a bowel movement.²

These agents work by dissolving or swelling in the intestinal fluid of the small and large intestines and form emollient gels that stimulate peristalsis, resulting in a bowel movement.^2,4 The usual onset of action is 12 to 24 hours after administration, but can take up to 72 hours.⁴ Bulk-forming agents are available in powders, tablets, capsules, chews, wafers, and gummies.² Patients should be advised to take each dose with at least 8 oz of fluid to avoid the potential for an intestinal block.^2,4 The use of these types of laxatives should be avoided in those with swallowing difficulties or esophageal strictures and may be inappropriate for patients who must restrict fluid intake.²

Table 3: Examples of OTC Products for Treating and Preventing Constipation

Brand Name (Active Ingredient)

Benefiber Products (wheat dextrin)

• Benefiber Fiber Caplets
• Benefiber Plus Heart Health Powder
• Benefiber Chewable Tablets
• Benefiber Powder
• Benefiber for Children
• Benefiber Powder Plus Calcium (300mg calcium)
• Benefiber Stick Packets

Citrucel Products (methylcellulose)

• Citrucel Powder with Smart Fiber (also available in a sugar-free option)
• Citrucel Caplets with Smart Fiber

Fiber Choice (inulin)

Fibercon Caplets (Calcium Polycarbophil)

Hydrocil (Psyllium)

Konsyl Products (psyllium hydrophilic mucilloid)

· Konsyl Fiber Caplets

· Konsyl Original

· Konsyl Easy Mix

· Konsyl Fiber Easy to Swallow Capsules

L’il Critters Fiber Gummy Bears

Little Remedies Fiber Gummies

Metamucil Products (psyllium husk)

• Metamucil Original
• Metamucil Fiber Powder Drink Mixes
• Metamucil Fiber MultiGrain Wafers
• Metamucil Fiber MultiHealth Capsules
• Metamucil Fiber Singles

Metamucil Clear and Natural (inulin)

Phillips Fiber Good Gummies

Unifiber (powdered cellulose)

Vitafusion Fiber Well Gummies

Vitafusion Fiber Well Weight Management Gummies

Emollient Agents

• Colace Capsules (docusate sodium)

Lubricant Laxatives

• Fleet Mineral Oil Enema (mineral oil 100%)
• Kondremul Emulsion (mineral oil 55%)

Saline Laxatives

• Magnesium Citrate Oral Solution
• Fleet Enema (monobasic sodium phosphate and dibasic sodium)
• Pedia-Lax Enema (monobasic sodium phosphate and dibasic sodium)
• Phillip's Milk of Magnesia Suspension (magnesium hydroxide)

Hyperosmotic Laxatives

• Fleet Gylcerin Suppository (gylcerin 2 g)
• MiraLAX (polyethylene glycol)

Stimulant Laxatives

• Dulcolax Tablets (bisacodyl)
• Senokot Tablets and Senokot Xtra (sennosides)
• Fletcher's Laxative for Kids (senna concentrate)

Combination Laxatives

• Senokot S tablets (sennosides and docusate sodium)

Hyperosmotic Agents

Hyperosmotic agents include polyethylene glycol 3350 (PEG 3350) and glycerin.² PEG 3350 is available as a powder for oral administration and typically produces a bowel movement in 12 to 72 hours—but may take as long as 96 hours.^2,4 PEG 3350 is considered to be a safe and effective laxative for the short-term treatment of constipation.² Common adverse effects (AEs) include bloating, cramping, and flatulence.^2,4 Patients with renal disease or irritable bowel syndrome should not take PEG 3350 without consulting their primary health care provider.^2,4 Glycerin is available in suppository form for lower bowel evacuation.² These suppositories typically produce a bowel movement within 15 to 30 minutes of administration and are considered safe for occasional use in all age groups.²

Emollient Agents

Also known as stool softeners, emollient agents contain docusate, available as docusate sodium or docusate calcium, and are classified as anionic surfactants that act in the small and large intestines to increase the wetting efficiency of intestinal fluid.² They are primarily used to prevent straining and painful defecation with anorectal disorders or in patients who should avoid straining, such as those with severe hypertension or cardiovascular disease, patients recovering from recent abdominal surgery or a myocardial infarction, or in postpartum women.^2,4 Stool softeners are often used in conjunction with stimulant laxatives and although generally welltolerated, they may cause diarrhea and mild abdominal cramping.^2,4

Lubricant Agents

Mineral oil is the only nonprescription lubricant, and its use is strongly discouraged for self-care because of the availability of safer agents.^2,4

Saline Laxatives

Saline laxatives should be taken with 8 oz of water to prevent dehydration.^2,4 Examples include magnesium citrate and magnesium hydroxide.^2,4 Oral magnesium is appropriate for the treatment of occasional constipation.^2,4 The onset of action is between 30 minutes and 6 hours after adminstration.^2,4 Possible AEs include nausea, vomiting, and mild abdominal cramping. Patients should be advised to take the recommended amount since these laxatives may cause electrolyte imbalances if used long term or at higher doses than were recommended.^2,4 Saline laxatives can interact with oral anticoagulants, digitalis, and some phenothiazines.

Stimulant Laxatives

Stimulant laxatives, such as bisacodyl and senna, work primarily in the colon to increase intestinal motility either by local irritation of the mucosa or via a more selective action on the intramural nerve plexus of intestinal smooth muscle.² These laxatives also increase secretion of water and electrolytes in the intestines.² The typical onset of action after oral administration is 6 to 10 hours, but may take up to 24 hours.^2,4 Bisacodyl suppositories may start working within 15 to 60 minutes of rectal administration.⁴ Use of these laxatives may cause cramping, colic, and increased mucus secretion.^2,4 Patients should be advised to never chew or crush bisacodyl tablets because doing so may cause stomach discomfort, faintness, and cramps.^2,4 Bisacodyl should not be taken within 1 hour after taking an antacid, proton pump inhibitor, histamine₂ antagonist, or milk because the interaction may break down the tablet’s coating too quickly, resulting in gastric or duodenal irritation.^2,4

Conclusion

During counseling, pharmacists should ascertain if self-treatment is appropriate and screen for potential drug—drug interactions and contraindications (Online Table 4). It is important to advise patients to adhere to the recommended dosage and administration guidelines and to use products as directed. Patients with chronic diarrhea should be advised to seek further evaluation from their primary health care provider.

In addition to providing patients with information about OTC products available for managing constipation, pharmacists can recommend nonpharmacologic measures that may help relieve constipation. Preventing constipation is often easier than treating the condition, but typically involves the same lifestyle modifications, including eating more fruits, vegetables, and whole grains that are high in fiber; drinking plenty of water and other liquids, if appropriate; avoiding or resolving medical conditions that restrict fluid intake; getting enough exercise; and not postponing bathrooms trips.^1,2

Table 4: Tips to Share with Patients Regarding Constipation^2,4

• Limit therapy with laxatives to 7 days, unless directed by primary health care provider

• Avoid taking laxatives within 2 hours of taking other medications

• Always consult your pharmacist or primary health care provider before using laxatives if you have any other medical conditions or currently take other medications

• Only take the recommended amount of the selected laxative, and adhere to directions

• Take laxatives at bedtime, especially if more than 6 to 8 hours is needed to produce results

• Do not take laxatives if you have severe abdominal pain, nausea, vomiting, cramping, and fever

• Do not give laxatives to children younger than 2 years, unless recommended by a primary health care provider

• Discuss chronic constipation or the frequent need for laxatives with your primary health care provider

Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.

References

• Constipation. National Institute of Diabetes and Digestive and Kidney Diseases website. www.niddk.nih.gov/health-information/health-topics/digestive-diseases/constipation/Documents/Constipation_508.pdf. Accessed June 17, 2015.
• Weitzel K. Constipation. In: Krinsky D, Ferreri S, Hemstreet B, et al, eds. Handbook of Nonprescription Drugs. 18th ed. Washington, DC: American Pharmacists Association; 2015.
• Basson M. Constipation. Medscape website. http://emedicine.medscape.com/article/184704-overview. Updated October 1, 2014. Accessed June 17, 2015.
• Dlugosz C. Constipation. The Practitioner's Quick Reference to Nonprescription Drugs. Washington, DC: American Pharmacists Association; 2012.