Thioridazine/Selected Moderate CYP2D6 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:

Very Serious. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Some medicines may slow down how quickly your liver processes thioridazine.

What might happen:

The level of thioridazine in your blood may increase. This may increase your risk of an irregular heartbeat, which may be life-threatening.

What you should do about this interaction:

Contact your healthcare professionals (e.g. doctor or pharmacist) right away about takings these medicines together. Let your doctor know right away if you notice an irregular heartbeat/palpitations or have 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.Thioridazine tablet, US prescribing information. Mutual Pharmaceutical September, 2014.
  • 2.Lamisil (terbinafine hydrochloride) tablet US prescribing information. Novartis Pharmaceuticals Corporation June, 2013.
  • 3.This information is based on an extract from the Certara Drug Interaction Database (DIDB) Platform, Copyright Certara 1999-2023..
  • 4.von Bahr C, Movin G, Nordin C, Liden A, Hammarlund-Udenaes M, Hedberg A, Ring H, Sjoqvist F. Plasma levels of thioridazine and metabolites are influenced by the debrisoquin hydroxylation phenotype. Clin Pharmacol Ther 1991 Mar;49(3):234-40.
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  • 6.American Geriatrics Society 2023 updated AGS Beers Criteria for potentially inappropriate medication use in older adults. J Am Geriatr Soc 2023 Jul;71(7):2052-2081.
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  • 8.Sensipar (cinacalcet hydrochloride) US prescribing information. Amgen Inc. March, 2019.
  • 9.Nakashima D, Takama H, Ogasawara Y, Kawakami T, Nishitoba T, Hoshi S, Uchida E, Tanaka H. Effect of cinacalcet hydrochloride, a new calcimimetic agent, on the pharmacokinetics of dextromethorphan: in vitro and clinical studies. J Clin Pharmacol 2007 Oct;47(10):1311-9.

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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.