December 6, 2023

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The Killer of Targeted Cancer Drugs: Grapefruit

The Killer of Targeted Cancer Drugs: Grapefruit

The Killer of Targeted Cancer Drugs: Grapefruit

Targeted cancer therapy drugs, lauded for their clear efficacy and low side effects, are hailed as advantageous weapons in the fight against malignancies.

However, these drugs can be defeated by a small fruit, especially abundant this season: grapefruit.



The Killer of Targeted Cancer Drugs: Grapefruit


The Killer of Targeted Drugs – Grapefruit

Grapefruit flesh is tender, juicy, slightly sweet with a tangy and bitter taste. It is also nutritionally rich, containing a variety of essential nutrients for the human body, such as vitamin C, vitamin B, calcium, iron, phosphorus, and more.

However, beyond its rich nutritional value, one should be particularly cautious about its interactions with certain medications when consuming grapefruit. Taking a medication alongside grapefruit is equivalent to taking an overdose of the drug. This is not an exaggeration, especially for cancer patients taking oral targeted therapy drugs.

This is because grapefruit contains a substance and its derivatives known as “furanocoumarins,” which strongly inhibit the activity of an enzyme in our bodies called “CYP3A4.” This enzyme happens to be a crucial metabolic enzyme responsible for breaking down, absorbing, and metabolizing targeted therapy drugs.

Consuming grapefruit inhibits the CYP3A4 metabolic enzyme. Reduced enzyme activity means that the drug cannot be metabolized, causing the targeted therapy drug to accumulate in the body without being excreted. The drug’s substantial accumulation in the body naturally affects its therapeutic effectiveness. In simpler terms, if you consume grapefruit along with targeted therapy drugs, it’s like taking a 20-fold dose of the medication. The danger of such a high dose of oral medication is evident.

Therefore, while taking targeted therapy drugs, grapefruit consumption should be strictly avoided. Besides grapefruit, oranges, pomelos, and lemons contain small amounts of furanocoumarins, which can mildly affect liver metabolic activity but do not have a significant impact. Therefore, cancer patients can consume these citrus fruits in moderation.

The drug instructions explicitly state the common anti-cancer drugs that should be avoided in combination with CYP3A4 strong inducers (grapefruit/grapefruit juice/grapefruit-containing beverages). These drugs include:

  • Gefitinib
  • Erlotinib
  • Afatinib
  • Crizotinib
  • Ceritinib
  • Alectinib
  • Lorlatinib
  • Brigatinib
  • Regorafenib
  • Imatinib
  • Sunitinib
  • Dasatinib
  • Nilotinib
  • Bevacizumab
  • Bortezomib
  • Cabozantinib
  • Ixazomib
  • Lenvatinib
  • Lapatinib
  • Pyrotinib
  • Palbociclib
  • Venetoclax
  • Dabrafenib
  • Trametinib
  • Darolutamide
  • Olaparib, and others.





The Killer of Targeted Cancer Drugs: Grapefruit

(source:internet, reference only)

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Important Note: The information provided is for informational purposes only and should not be considered as medical advice.