Chapter Updates

Content Update for Chapter 16, "Constipation"

FDA Approval of OTC MiraLAX

The following information supplements and updates text in Chapter 16, "Constipation," in the Handbook of Nonprescription Drugs, 15th Edition.

MiraLAX

MiraLAX (polyethylene glycol 3350; PEG 3350) is the first laxative to be approved by the Food and Drug Administration (FDA) as an Rx-to-OTC switch in over 30 years. FDA approved the switch on October 6, 2006, and granted the product 3 years of marketing exclusivity.1 The product is approved for children and adults 17 years of age or older. Use in children younger than 16 years should be supervised by a primary care provider.

Mechanism of Action  MiraLAX, an oral agent, belongs to the class hyperosmotics, as does glycerin suppositories, a nonprescription laxative administered rectally. Hyperosmotics cause water to be retained in the colon, thereby stimulating a bowel movement.

Indications  As for other nonprescription laxatives, this agent is approved for occasional constipation. It usually produces a bowel movement in 1 to 3 days. Use is not to exceed 7 days.2

Dosage and Administration Guidelines  MiraLAX is available in powder form only. Seven-dose (4.1 oz; 119 g) and 14-dose (8.2 oz; 238 g) containers are available. The product contains no inactive ingredients.

The nonprescription dosage of 17 g taken once a day is the same as the prescription dosage. The bottle cap serves as a measuring device, with the white section holding 17 g. The patient should carefully measure the dose, pour the powder into 4 to 8 ounces of a beverage (cold, hot, or room temperature), and then stir the powder until it is dissolved.2

Patients should be advised that they might have loose, watery, and more frequent stools.2

Safety Considerations  According to package labeling,2 a health care provider should be consulted before using this product if the following symptoms or conditions exist:

Signs or symptoms occurring during product use that warrant medical attention include:

The most recent clinical study3 of MiraLAX involved its chronic use for chronic constipation. In this double-blind, placebo-controlled, parallel, multicenter study, 304 enrolled patients were randomized to receive 17 g of the laxative or placebo for 6 months. Of these patients, 52% of PEG patients and 11% of placebo patients achieved the primary parameter for successful treatment (P < 0.001), defined as relief of modified Rome criteria for constipation for 50% or more of the treatment weeks. Researchers found no significant differences between the patient groups with regard to adverse events except for gastrointestinal side effects, with diarrhea, flatulence, and nausea occurring most frequently in PEG patients; however, the difference between patient groups was not significant. Researchers concluded that MiraLAX is safe and effective for use in patients with chronic constipation for 6 months.

An earlier study4 by these authors concluded that MiraLAX could safely and effectively treat constipation in adult and elderly patients for periods up to 12 months, with no evidence of tachyphylaxis. By extension, these findings should support the safety of its use for 7 days in patients who meet the nonprescription label criteria.

References

  1. FDA approval letter for MiraLAX NDA 22-015. Rockville, MD: US Food and Drug Administration; December 10, 2006. Available at: http://www.fda.gov/cder/foi/appletter/2006/022015s000ltr.pdf. Accessed June 26, 2007.
  2. MiraLAX [package insert]. Kenilworth, NJ: Schering Plough Healthcare Products; 2006.
  3. Dipalma JA, Cleveland MV, McGowan J, et al. A randomized, multicenter, placebo-controlled trial of polyethylene glycol laxative for chronic treatment of chronic constipation. Am J Gastroenterol. 2007 Mar 31; [Epub ahead of print].
  4. Dipalma JA, Cleveland MV, McGowan J, et al. An open-label study of chronic polyethylene glycol laxative use in chronic constipation. Aliment Pharmacol Ther. 2007;25:703-8.