FDA Warns of Heart Risk with Loperamide Overdose
Permanent and fatal arrhythmias tied to misuse of loperamide
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.”
The problem appears to have exploded in recent years. More than half of the 48 cases of serious heart problems reported to the FDA since the drug was approved in 1976 occurred in the short span from 2010 to 2015. Of those cases, 31 resulted in hospitalization and 10 in death. The most severe cases were among people taking four to 100 times the recommended loperamide dose.
“Consider loperamide as a possible cause of unexplained cardiac events including QT interval prolongation, torsades de pointes or other ventricular arrhythmias, syncope, and cardiac arrest,” the FDA recommended to clinicians.
Standard toxicology and opioid drug screens don’t include an assay for loperamide and will turn up a negative result in the presence of loperamide. If loperamide toxicity is suspected, blood levels should be measured by specifically requesting the test for the drug, the FDA suggested.
Antiarrhythmic drugs have been ineffective in many reported cases of loperamide-associated torsades de pointes, the agency added, so electrical pacing or cardioversion should be considered.
The FDA said it will continue to watch this safety issue to see if additional actions are needed.
Filed under: General Problems
MANY meds. can cause horrible problems when taken correctly! I have congestive heart failure & have had at least 6 mini strokes after taking Celebrex as directed for less than 9mo. I now have to be on 3 strong bp meds. & my bp rarely goes below 155/109 & has gone as high as 226/120 w/o all 3 meds.! Or how about Tylenol that damaged my liver so bad that it lost about 75% of it’s function, Thank God, since stopping, I have gotten back 80% function & climbing, but I can never take Tylenol again!! I have been on oxycodone almost 20yrs. & have no damage from it as all it has done is give me some of the life that Celebrex & epidurals took away! Fibro. & RA hurt & slowed my down, but Celebrex & cortisone completely disabled me & ruined my life!!
Where are the protests about these as they have maimed & killed 1000’s more than opioids!!
And in other news…water is wet. Aren’t you glad that the State is adept at playing Captain Obvious? If a drug has any abuse potential, the folks that literally live and die for that sort of thing will have found if it can be abused and how to best abuse it before the ink is dry on the marketing approval. As loperamide. from a medicinal chemistry standpoint, shares a fair number of similarities with diphenoxylate (opioid in the anti-diarrhea drug Lomotil) and fentanyl, it’s no wonder that someone would discover it’s abuse potential. In addition, cut off somebody’s opioid pain medication and the one thing that loperamide will do is calm the GI tract, especially the bowel down.
As to the cardiac toxicity, I do know that another synthetic opioid, d-propoxyphene, has cardiac toxicity at higher doses because it and it’s major metabolite also have anesthetic effects more potent than lidocaine. That’s one of the major reasons that the FDA pulled it from the market. It acts much like a Class 1c anti-arrhythmic drug; anti-arrhythmic drugs can also cause arrhythmias. I wonder if the brain trusts at the FDA have considered that loperamide is behaving in an analogous way when serum concentrations become adequately elevated?
I’ve taken it once within normal dose parameters for its intended purpose (while I happened to be in slight yet manageable withdrawal from a documented Rx mess up… just couldn’t be glued to the bathroom that day) and it seemed to help the other symptoms as well. I don’t get why people are taking huge doses of it? Maybe I’m just odd because I’m pretty opiate naive? Just seems kinda screwball that this is like some new big thing that mega doses of something can mess up your heart. Look at nsaids and benadryl. Many blessings and I hope you’re feeling better Steve