Higher than recommended doses of diarrhea drug loperamide (Imodium) can cause serious and even fatal cardiac arrhythmias, the FDA warned.
Although some of the 48 cases of QT interval prolongation, torsades de pointes, cardiac arrest, syncope, and other serious cardiac events reported to the agency have been unintentional misuse of more than the maximum daily dose for adults (8 mg in over-the-counter products; 16 mg in prescription use), most have been intentional abuse.
“The majority of reported serious heart problems occurred in individuals who were intentionally misusing and abusing high doses of loperamide in attempts to self-treat opioid withdrawal symptoms or to achieve a feeling of euphoria,” the agency noted in a Drug Safety Communication.
Loperamide is a mu-opioid agonist that acts primarily in the gut but, in high doses, has psychoactive effects. It has recently been recognized as a drug of abuse and is recommended in internet chat forums for treating symptoms of opioid withdrawal.
Taking loperamide with drugs that interact with it, including ranitidine (Zantac), increases the risk. These combinations, too, are often intentional in “attempts to increase its absorption and penetration across the blood-brain barrier, inhibit loperamide metabolism, and enhance its euphoric effects.”
