Grapefruit & TKIs
A Review: Interview with Dr. Lin, Does Grapefruit Interfere with TKIs?
The interview with Dr. Lin covered topics that we should know about with regards to cytochrome P450 and its significance in processing TKI* medication. Cytochrome P450 is part of a system important in metabolizing medicine in the liver. Cytochromes metabolize oily (fat-soluble) chemicals so they can be eliminated from the body via the kidneys. The problem arises when a drug inhibits a cytochrome from functioning at its optimum and the substances that the cytochrome was supposed to clear have now “piled up” in the body, leading to higher than expected levels of the drug.
Additionally, there are genetic variations of what types of cytochrome a person can have due to their heritage. For example, one population may have a higher level of one cytochrome versus another because of regional variations of what food grows in the region. This increase of one cytochrome has helped the population digest the regional food better. Hence, you hear of one patient experience a heavy side effect whereas another had fewer side effects from the same medication. Because of these variations, pharmacogenetics is a new science which determines the cytochrome profile of a patient, providing the physician with a guide to what medication and what dosage best fit the patient.
Review of Drug Interactions and Cytochrome Here (limit of 5 clicks per person)
Here is an extensive list of cytochrome modulators from Wikipedia:
Alcoholic drinks, dairy products, caffeinated beverages, green leafy vegetables, and grapefruit are some common foods that can have unforeseen drug interactions. This article gives a very clear message: moderation!
A digital image of what a Cytochrome P450 looks like Here.
*TKIs stand for Tyrosine Kinase Inhibitors and they are the type of targeted medicine that are recommended for Stage IV ALK Lung Cancer, according to NCCN guidelines. They include first generation drug Crizotinib, second generation drugs Certinib, Alectinib, Brigatinib (and Ensartinib, still in trials) and third generation drug Lorlatinib.