In January, the Food and Drug Administration (FDA) issued an updated Drug Safety Communication related to abuse of the over-the counter (OTC) antidiarrheal drug, loperamide (Imodium A-D and others). Loperamide works by stimulating certain opioid receptors in the gastrointestinal tract, thereby slowing bowel motility and decreasing loose stools. When higher doses are taken, the drug can cross the blood-brain barrier, resulting in the stimulation of opioid receptors in the central nervous system. People may intentionally abuse loperamide to seek enhanced euphoric effects, prevent opioid withdrawal symptoms, or just control diarrhea. Some patients may experience an unintentional overdose because they're taking other drugs that may interact with loperamide and raise its circulating levels.

In this update, the FDA repeats the warning from its 2016 Drug Safety Communication that taking higher than recommended doses of loperamide, intentionally or not, could cause serious cardiac complications or death because of the drug's ability to prolong the QT interval, induce torsades de pointes or other life-threatening ventricular arrhythmias, produce syncope, and cause cardiac arrest.

Because reports of loperamide overdose and serious cardiac events have continued, the agency is now working with manufacturers to create packaging (such as blister packs) that will more clearly indicate the single dose for consumers and limit the number of doses in a package. The OTC dose of loperamide should not exceed 8 mg/day; for prescription-strength loperamide, 16 mg/day is the maximum dose. In case reports examined by the FDA, the mean dose was 195 mg/day.

Nurses should assess patients for use of OTC loperamide and teach them about the risk of serious cardiac adverse effects from taking more than the recommended daily dose. To read the full FDA Drug Safety Communication, go to http://www.fda.gov/Drugs/DrugSafety/ucm594232.htm.