Drug interactions
Grapefruit + Red yeast rice
Severity: Moderate
Grapefruit and Red yeast rice: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Red yeast rice contains monacolin K, which is chemically identical to lovastatin and is metabolized by CYP3A4. Grapefruit juice can raise exposure to the statin, increasing the risk of myopathy and rhabdomyolysis.
What this interaction means in plain words
Grapefruit and Red yeast rice can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Grapefruit components inhibit intestinal CYP3A4, reducing first-pass metabolism of monacolin K.
What to do
Avoid large amounts of grapefruit juice while taking red yeast rice. Advise patients to report unexplained muscle pain, weakness or dark urine.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Red yeast rice
- Red yeast rice + Ritonavir Contraindicated
- Red yeast rice + Saquinavir Contraindicated
- Red yeast rice + Tipranavir Contraindicated
- Atazanavir + Red yeast rice Major
- Atorvastatin + Red yeast rice Major
- Conivaptan + Red yeast rice Major
Frequently asked questions
Can I take Grapefruit with Red yeast rice?
MediHelp rates the interaction as moderate. Grapefruit and Red yeast rice can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Red yeast rice contains monacolin K, which is chemically identical to lovastatin and is metabolized by CYP3A4. Grapefruit juice can raise exposure to the statin, increasing the risk of myopathy and rhabdomyolysis.
How serious is the interaction between Grapefruit and Red yeast rice?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid large amounts of grapefruit juice while taking red yeast rice. Advise patients to report unexplained muscle pain, weakness or dark urine.
What other medicines interact with Red yeast rice?
MediHelp also lists interactions of Red yeast rice with, for example, Ritonavir, Saquinavir, Tipranavir. The full list is on the Red yeast rice page.
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