Grapefruit, alcohol, milk: when the contents of the plate interfere with medication

Swallowing a pill isn't like flipping a switch. Part of the active ingredient is normally broken down in the digestive tract by enzymes, and doses are calculated with this in mind… except that food can disrupt this process. A glass of juice here, a coffee there, a slightly too boozy dinner, and the effect of the treatment can change drastically: its effectiveness diminishes, and side effects appear, sometimes without warning. The most well-known example is alcohol, which is not recommended with many medications because it amplifies the effects or reduces tolerance, but it's not the only unwelcome guest at the table.

Grapefruit, a small fruit, a big trap

Grapefruit, often sold as pomelo, can be a real troublemaker: its furanocoumarins block the CYP3A4 enzyme, responsible for breaking down many medications, allowing more of the active ingredient to circulate in the body, with a risk of overdose. And don't count on cooking to solve the problem; both raw and cooked grapefruit can be enough, sometimes even with just a single glass of juice. Depending on the specific molecules involved, this can affect cholesterol-lowering drugs, anxiolytics, antidepressants, anti-inflammatories, or anticoagulants, while some citrus fruits can also cause problems. Even "minor" medications have their rules: an antidiarrheal like Smecta should be taken at least two hours apart from other medications to avoid interfering with their absorption, and dairy products, coffee, or a diet very high in vitamin K can also disrupt certain prescriptions. Ultimately, the instructions and the pharmacist remain the best allies, especially when the prescription interferes with cooking habits.