Does Red Yeast Rice Interact With Tagrisso?
In our latest question and answer, our pharmacist discusses the interaction between Tagrisso and red yeast rice.

Question
Does Red Yeast Rice interact with Tagrisso (osimertinib)? Thank you.

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated Apr 21, 2025
Key points
- Red yeast rice is a type of yeast that is grown on rice and used as a dietary supplement. It is a natural inhibitor of the enzyme HMG-CoA reductase, which is involved in cholesterol production.
- Taking red yeast rice and Tagrisso (osimertinib) together may increase the risk of side effects such as muscle pain and weakness, as Tagrisso is an inhibitor of the CYP3A4 enzyme and red yeast rice is metabolized, at least partially, by the CYP3A4 enzyme.
Answer
Thanks for reaching out! Yes, red yeast rice has a theoretical interaction with Tagrisso (osimertinib).
We have comprehensive interaction details that can be found on the 'drug-herbal interaction' part of our website, but the summary of the interaction is as follows:
- Red yeast rice is metabolized, at least partially, by the CYP3A4 enzyme
- Tagrisso is known to be an inhibitor of the CYP3A4 enzyme
- Taking red yeast rice and Tagrisso may increase the risk of certain side effects, such as muscle pain and weakness, due to increased concentrations of red yeast rice in the blood due to CYP3A4 inhibition
What Is Red Yeast Rice?
Red yeast rice is a type of yeast that is grown on rice and is commonly used as a dietary supplement. It contains compounds known as monacolins, which are natural inhibitors of the enzyme HMG-CoA reductase. Inhibiting HMG-CoA reductase is the same mechanism via which 'statin' drugs, like Lipitor and Zocor, work.
HMG-CoA reductase is involved in the production of cholesterol in the body, and blocking its activity leads to a reduction in cholesterol levels.
Interaction Details
Now, the interaction between Tagrisso and red yeast rice is an interesting one since, in this case, we have a drug potentially interfering with an herbal. The prescribing information for Tagrisso states the following:
osimertinib is a competitive inhibitor of CYP3A, but not CYP2C8, 1A2, 2A6, 2B6, 2C9, 2C19, 2D6 and 2E1 in vitro.
Since red yeast rice works in essentially the same way as 'statin' medications, this interaction increases the risk of statin-like side effects, such as muscle pain and weakness.
It is not known how severe this interaction is, or at what doses of red yeast rice it becomes clinically significant as comprehensive research hasn't been done in this area.
It is crucial to be aware of the potential effects of taking red yeast rice and Tagrisso (osimertinib) together.
If you experience any adverse effects from the combination, it is important to seek medical attention.
To ensure proper monitoring and prevent any potential interactions, it is important to inform your doctor of all medications, including supplements, that you are taking.
Final Words
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References
- Interaction between Red Yeast Rice and CYP450 Enzymes/P-Glycoprotein and Its Implication for the Clinical Pharmacokinetics of Lovastatin, PubMed
- Assessment of Extracts from Red Yeast Rice for Herb-Drug Interaction by in-vitro and in-vivo assays, Nature
- Red Yeast Rice: A Systematic Review of the Traditional Uses, Chemistry, Pharmacology, and Quality Control of an Important Chinese Folk Medicine, Frontiers
- Tagrisso Prescribing Information, AccessFDA
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Dr. Brian Staiger, PharmD
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