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.

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Key Concepts

1. 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.
2. 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.
3. 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.
4. Hyperosmotic laxatives (like PEG 3350 or MiraLAX) work by pulling water into the colon WITHOUT being systemically absorbed.
5. 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.
6. Lubricant laxatives (like mineral oil) generally have a less favorable adverse effect profile and are less preferred over other options.
7. 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.
8. 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.
9. 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").
10. For pregnant women, consider bulk-forming laxatives or docusate as a first-line option.
11. For children older than 2 years of age, consider docusate, senna, or magnesium hydroxide (Milk of Magnesia) as a first-line option.
12. 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.