CHICAGO (WOWO) — Millions of people taking commonly prescribed medications are being warned that a popular summer fruit could interfere with how their bodies process certain drugs, potentially causing serious side effects.
Doctors say grapefruit — often found in juices, smoothies and summer cocktails — can alter the way some medications are absorbed, increasing drug levels in the bloodstream beyond what is intended.
Dr. Nicole James, a physician based in Illinois and a clinical research fellow in the Department of Dermatology at Stanford University, told SWNS that people taking certain medications should discuss grapefruit consumption with their healthcare providers.
“Grapefruit is a pleasant snack for most, but it is important to disclose large amounts of grapefruit use to your doctor because it can interact with an array of medications,” James said.
The concern centers around natural compounds in grapefruit, including furanocoumarins and flavonoids, which can interfere with an enzyme known as cytochrome P450 3A4, or CYP3A4.
The enzyme helps the body break down many oral medications so they can be properly processed.
“When you ingest grapefruit, it blocks this enzyme,” James explained.
She said that when CYP3A4 is inhibited, medications that would normally be partially broken down in the digestive system can instead enter the bloodstream in larger amounts.
“This causes drugs that would normally be broken down in the gut wall to instead pass through intact, leading to significantly higher-than-intended blood levels of the medication,” James said.
James warned that people do not necessarily need to consume large quantities of grapefruit for an interaction to occur.
“As little as one grapefruit or 200 mL of juice can cause a clinically relevant increase in medication concentrations, and the effect can last up to 72 hours because grapefruit irreversibly inactivates CYP3A4 enzyme,” she said.
Because grapefruit juice is commonly used in mixed drinks and blended beverages, experts say consumers should check ingredients in cocktails, smoothies and fruit drinks.
Popular grapefruit-based beverages include palomas, greyhounds, some margaritas and sea breezes.
Doctors say several categories of medications can be impacted by grapefruit consumption.
For people taking statins to lower cholesterol, increased medication levels may raise the risk of side effects.
“Patients taking statins could experience higher levels than normal, which can cause muscle breakdown and cramps,” James said.
Certain blood pressure medications, including amlodipine, may also be affected. James said patients could experience dizziness and dangerously low blood pressure.
Sedatives may present another concern. She said medications such as midazolam could lead to “extreme drowsiness and even slowed breathing” when combined with grapefruit.
Some antidepressants, including sertraline, also carry warnings related to grapefruit interactions.
James said anyone who consumes large amounts of grapefruit while taking medications affected by the fruit should monitor for symptoms and avoid additional grapefruit until they speak with a healthcare professional.
“If patients ingest a large amount of grapefruit while on these medications, they should monitor for any symptoms and avoid ingesting any more grapefruit,” James said.
She added that patients should seek medical attention if they experience concerning symptoms.
Health experts also remind patients that grapefruit is not the only food ingredient that can interfere with medications.
Foods high in vitamin K, including leafy green vegetables and cranberry juice, can affect people taking warfarin, a blood thinner commonly prescribed to reduce the risk of heart attack and stroke.
Dairy products may reduce the effectiveness of some antibiotics, including ciprofloxacin, as well as certain bisphosphonates used in osteoporosis treatment.
Doctors advise patients to review food and drink interactions with their healthcare providers and pharmacists when starting new medications or making significant changes to their diets.
