Quinidine; Quinine/Azithromycin; Erythromycin; Troleandomycin 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:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Your antibiotic may slow down how quickly your liver processes quinidine or quinine.

What might happen:

The amount of quinidine or quinine in your blood may increase and cause serious side effects, such as an irregular heartbeat.

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 notice an irregular heartbeat or have any dizziness or fainting episodes.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.Qualaquin (quinine sulfate) US prescribing information. Sun Pharmaceutical Industries, Inc. August, 2019.
  • 2.Zhao XJ, Ishizaki T. A further interaction study of quinine with clinically important drugs by human liver microsomes: determinations of inhibition constant (Ki) and type of inhibition. Eur J Drug Metab Pharmacokinet 1999 Jul-Sep;24(3):272-8.
  • 3.Zithromax (azithromycin oral) US prescribing information. Pifzer Labs April, 2019.
  • 4.E.E.S. (erythromycin ethylsuccinate) US prescribing information. Arbor Pharmaceuticals, Inc. April, 2018.
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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.