College of Pharmacy
HelixTalk Episode #46 - Self-Care of Constipation
Date posted: July 12, 2016, 6:00 am
In this episode, we discuss self-care of constipation including bulk-forming laxatives, hyperosmotic laxatives, emollient laxatives, lubricant laxatives, saline laxatives, and stimulant laxatives.
- Patients with constipation and any bleeding, fever (or other signs of infection), concurrent nausea/vomiting, or persistent symptoms (lasting more than two weeks) are not appropriate for self-care.
- Basic non-pharmacologic therapies for constipation include adequate hydration (at least two liters per day), improved diet (focusing mainly on more fruits and vegetables), and exercise.
- Bulk-forming laxatives (such as psyllium, polycarbophil, methylcellulose, and wheat dextrin) are effective for preventing (not treating) constipation and must be taken with plenty of fluid.
- Hyperosmotic laxatives (like PEG 3350 or MiraLAX) work by pulling water into the colon WITHOUT being systemically absorbed.
- Emollient laxatives (also known as stool softeners, like docusate or Colace) work as a detergent to mix fatty and aqueous particles in the stool. Stool softeners are more effective in preventing straining rather than treating constipation.
- Lubricant laxatives (like mineral oil) generally have a less favorable adverse effect profile and are less preferred over other options.
- There are several types of saline laxatives on the market. These work similarly to hyperosmotic laxatives, but ARE systemically absorbed. Popular saline laxative options include:
- Magnesium hydroxide (Milk of Magnesia) - good option for occasional constipation
- Magnesium citrate - usually reserved for more severe symptoms or even bowel preparation prior to colonoscopy
- Sodium phosphate (Fleets enema) - reserved for severe symptoms. Maximum of one dose per day for a maximum of three consecutive days. Use with caution in patients with renal impairment, heart failure, elderly, and cirrhosis.
- Stimulant laxatives (senna and bisacodyl) work by irritating the GI lining and causing increased peristalsis. These are very commonly used, especially senna with docusate in a combination product.
- For opioid-induced constipation, stimulant laxatives and PEG 3350 (MiraLAX) have the most supporting data. Do not use bulk-forming laxatives. Docusate alone is unlikely to be effective ("all mush no push").
- For pregnant women, consider bulk-forming laxatives or docusate as a first-line option.
- For children older than 2 years of age, consider docusate, senna, or magnesium hydroxide (Milk of Magnesia) as a first-line option.
- Be very careful with saline laxatives in the elderly or those with a sodium restriction (eg, renal impairment, cirrhosis, or heart failure). The components of saline laxatives are systemically absorbed and will accumulate in patients who have difficulty eliminating these medication.