From the Guidelines
Patients taking mycophenolate (CellCept, Myfortic) should avoid consuming grapefruit or grapefruit juice due to potential drug interactions. Grapefruit contains compounds that can inhibit the CYP3A4 enzyme, which may affect how mycophenolate is metabolized in the body, potentially leading to increased immunosuppression, gastrointestinal disturbances, or bone marrow suppression 1. Although the interaction between grapefruit and mycophenolate is considered moderate, avoiding grapefruit products can help ensure consistent therapeutic levels and prevent unpredictable effects.
Key Considerations
- The amount and type of grapefruit juice consumed can impact the severity of the interaction, but it is best to err on the side of caution and avoid it altogether 1.
- Other citrus fruits like oranges, lemons, and limes are generally safe alternatives.
- Patients should inform their healthcare provider about all foods, supplements, and medications they consume to monitor for potential interactions with mycophenolate therapy.
Clinical Implications
- The potential for increased mycophenolate blood levels due to grapefruit consumption highlights the importance of careful monitoring and dose adjustments as needed.
- Healthcare providers should advise patients taking mycophenolate to avoid grapefruit and grapefruit juice, as recommended for other medications that interact with CYP3A4, such as ciclosporin 1.
From the Research
Interactions between Mycophenolate (Cellcept) and Grapefruit
- There are no direct studies on the interaction between mycophenolate (Cellcept) and grapefruit in the provided evidence.
- However, the studies suggest that grapefruit juice can increase the concentrations of many drugs in humans by suppressing the cytochrome P450 enzyme CYP3A4 in the small intestine wall 2, 3.
- Mycophenolate is metabolized by the liver enzyme uridine diphosphate glucuronyltransferase (UGT) and not by CYP3A4, but it can be affected by other mechanisms such as inhibition of organic anion transporting polypeptide (OATP) 3, 4.
- It is recommended that patients refrain from drinking grapefruit juice when taking drugs that are extensively metabolized, unless a lack of interaction has already been demonstrated for the drug 2.
- The components of grapefruit juice that are most likely to cause interactions are psoralen derivatives and the flavonoid naringenin 2.
- Other fruit juices, such as orange, apple, and pomelo, can also precipitate drug interactions, although the extent of the interaction may vary depending on several factors, including the volume of juice consumed and the type of fruit 5.
- Patients should be counseled on potential food-drug interactions, including those with grapefruit, to avoid adverse effects and optimize medication therapy 6.