A pharmacist has issued a warning about common foods and drinks that can interfere with medications, urging people to be mindful during the festive season. Ian Budd, Prescribing Pharmacist at Chemist4U, highlighted that everyday choices like grapefruit juice, leafy greens, cranberry juice, dairy products, and aged cheeses can affect how well medicines work or increase side effects.
Grapefruit is the biggest culprit, as it blocks an enzyme in the liver that helps break down certain drugs. This can make medications like statins, blood pressure tablets, some antidepressants, and immune-suppressing drugs more potent, increasing side effects. Even one glass of grapefruit juice can have an effect lasting up to a day, so it is safest to avoid it completely with these medications.
Leafy greens such as spinach, kale, and broccoli are rich in vitamin K, which can interfere with blood thinners like warfarin. Sudden changes in vitamin K intake can make warfarin less effective or too strong, so pharmacists recommend keeping intake consistent rather than avoiding greens altogether. Cranberry juice, often seen as healthy, can also affect warfarin, potentially making the blood too thin and increasing the risk of bruising or bleeding.
Dairy products like milk, cheese, and yoghurt can bind to certain antibiotics, such as tetracyclines and fluoroquinolones, reducing their absorption. To avoid this, take these antibiotics a couple of hours before or after consuming dairy. Aged cheeses, cured meats, and fermented products contain tyramine, which can cause a sudden rise in blood pressure, particularly in those taking MAO inhibitors for depression.
Budd emphasised that these interactions can make a real difference in treatment effectiveness. He advised checking with a pharmacist before making any dietary changes while on medication, especially during the Christmas season when festive foods are abundant.
