Loperamide/CYP3A4; CYP2C8; P-glycoprotein (P-gp) Inhibitors Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Your medicine may increase the amount of loperamide that enters your brain.

What might happen:

You may have more side effects than normal from your loperamide.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Let your doctor know right away if you experience excessive drowsiness, deep sleep, slowed breathing, slow pulse, nausea, or vomiting.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.USFood and Drug Administration. FDA Drug Safety Communication: FDA warns about serious heart problems with high doses of the antidiarrheal medicine loperamide (Imodium), including from abuse and misuse. available at: http://www.fda.gov/downloads/Drugs/DrugSafety/UCM505108.pdf June 7, 2016.
  • 2.Zokinvy (lonafarnib) US prescribing information. Eiger BioPharmaceuticals, Inc. November, 2020.
  • 3.Kim TE, Lee H, Lim KS, Lee S, Yoon SH, Park KM, Han H, Shin SG, Jang IJ, Yu KS, Cho JY. Effects of HM30181, a P-glycoprotein inhibitor, on the pharmacokinetics and pharmacodynamics of loperamide in healthy volunteers. Br J Clin Pharmacol 2014 Sep;78(3):556-64.
  • 4.Niemi M, Tornio A, Pasanen MK, Fredrikson H, Neuvonen PJ, Backman JT. Itraconazole, gemfibrozil and their combination markedly raise the plasma concentrations of loperamide. Eur J Clin Pharmacol 2006 Jun;62(6):463-72.
  • 5.Sadeque AJ, Wandel C, He H, Shah S, Wood AJ. Increased drug delivery to the brain by P-glycoprotein inhibition. Clin Pharmacol Ther 2000 Sep; 68(3):231-7.
  • 6.Imodium (loperamide hydrochloride) US prescribing information. Johnson & Johnson Consumer Inc. October, 2016.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.