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What's Up Magazine

When Food and Medications Collide

Dec 06, 2018 12:00AM ● By Brian Saucedo

By Kelsey Casselbury

Every time you fill a medication prescription, a small leaflet full of information comes stapled to the bag that the pharmacist packs up the drug in—do you automatically toss it in the trash? If so, consider scanning through it the next time you fill a prescription, particularly if you’re starting a new medication. You might be surprised at some of the limitations taking that drug puts on your life, including what foods and drinks you consume. Check out below five prescription drugs that interact with foods you might eat daily and one over-the-counter medications that collides with your favorite post-work tipple. 

Grapefruit Juice

Interacts with: Cholesterol-lowering statins, amphetamines like Adderall, antihistamines, blood pressure drugs

Grapefruit juice, which contains compounds that other citrus juices do not, are one of the most publicized items that interact with drugs, but it’s both over- and under-reported. For example, it’s not emphasized how serious the interaction can be—just one glass of juice can lead to dangerous blood levels of cholesterol-lowering statins such as Lipitor and Zocor that take up to four days to wear off. On the other hand, most medications (including all over-the-counter drugs) don’t interact with grapefruits or just have mild interactions, which some people might be surprised to learn . For example, grapefruit juice reduces the effectiveness of some ADHD drugs such as Adderall. 

Green Leafy Vegetables

Interacts with: Blood-thinning drugs such as warfarin

Vitamin K isn’t a supplement that you hear about often, but it’s vital in helping your blood clot—the exact opposite of what blood-thinning drugs like warfarin are supposed to do. If you consume too much vitamin K, prevalent in not only green leafy vegetables, but also broccoli and Brussels sprouts, it decreases the medication’s ability to prevent that clotting. However, it’s just a problem if you suddenly increase your intake of vitamin K, so you can still enjoy these healthy veggies a couple of times a week without risk. 

Tyramine-Rich Foods 

Interacts With: Antidepressants known
as monoamine oxidase inhibitors

The interaction between Tyramine-rich foods and monoamine oxidase inhibitors (MAOIs) such as Marplan, Nardil, and Emsam is dangerous. Therefore, if you take an MAOI for depression, avoid foods that are rich in the amino acid tyramine, which naturally helps the body regulate blood pressure. This includes aged cheese, dried fruit, cured meats, wine, beer, avocado, and soy sauce. Too much, and your blood pressure can spike, increasing the risk of the stroke. 

Salt Substitutes

Interacts With: ACE inhibitors for high blood pressure, digoxin for heart failure

Salt substitutes replace sodium with potassium, which is great for people trying to cut back on their sodium intake. It’s not so fantastic for people already managing high blood pressure with ACE inhibitors, which also increase potassium in the body. When those levels get too high, you can experience an irregular heartbeat or heart palpitations. For those taking digoxin for heart failure, salt substitutes can decrease the effectiveness of the drug. Avoid, too, other potassium-rich foods, such as bananas. 


Interacts with: Acetaminophen (Tylenol)  

The OTC painkiller acetaminophen, sold under the brand name Tylenol, is one of the most popular ways to stem a headache, but mixing it with alcohol is simply asking for a bad time. Not only can the combination cause liver damage—particularly if you have three or more drinks a day—but research also shows it puts you at risk of kidney disease, too.

Dairy Foods

Interacts With: The antibiotics tetracycline and fluoroquinolones

Taking certain antibiotics with milk, yogurt or other dairy foods aren’t harmful, luckily, but it certainly won’t do your body (or the illness that you’re taking antibiotics for) any favors. When you take tetracycline (which is prescribed for bacterial infections including acne) or fluoroquinolones (often used to treat respiratory or urinary tract infections) like Cipro or Levaquin, the dairy binds to the medication and forms a complex that’s impossible for your body to absorb. It’s not going to hurt you, but the medication’s effect is rendered moot. 

Bottom line: If you take a medication, always read the included information to ensure your diet isn’t nulling the effectiveness of the drug or actually causing you harm. Even better, talk to your doctor or a pharmacist about how you can stay safe while taking prescription and OTC meds.